{"id":29457,"date":"2026-07-03T17:44:25","date_gmt":"2026-07-03T09:44:25","guid":{"rendered":"https:\/\/www.bestpcbs.com\/blog\/?p=29457"},"modified":"2026-07-03T17:44:27","modified_gmt":"2026-07-03T09:44:27","slug":"fr408hr","status":"publish","type":"post","link":"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/","title":{"rendered":"Isola FR408HR PCB Material Guide for High-Speed PCB"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_84 ez-toc-wrap-left counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/#What_Is_FR408HR_PCB_Material\" >What Is FR408HR PCB Material?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/#Why_Is_Isola_FR408HR_Used_for_High-Speed_PCB_Design\" >Why Is Isola FR408HR Used for High-Speed PCB Design?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/#What_Is_the_Dielectric_Constant_and_Dk_Value_of_FR408HR\" >What Is the Dielectric Constant and Dk Value of FR408HR?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/#What_Is_the_Loss_Tangent_and_Df_Value_of_FR408HR\" >What Is the Loss Tangent and Df Value of FR408HR?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/#What_Thickness_Options_Are_Available_for_Isola_FR408HR_PCB_Material\" >What Thickness Options Are Available for Isola FR408HR PCB Material?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/#FR408HR_Material_Properties_Datasheet_Overview\" >FR408HR Material Properties &amp; Datasheet Overview<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/#FR4_vs_FR408HR_What_Is_the_Difference\" >FR4 vs FR408HR: What Is the Difference?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/#FR408_vs_FR408HR_vs_FR408HRS_How_Should_You_Choose\" >FR408 vs FR408HR vs FR408HRS: How Should You Choose?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/#FR408HR_vs_370HR_Which_Material_Is_Better_for_Your_PCB_Project\" >FR408HR vs 370HR: Which Material Is Better for Your PCB Project?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/#FR408HR_vs_Rogers_4350B_Which_One_Is_Suitable_for_High-Frequency_PCB\" >FR408HR vs Rogers 4350B: Which One Is Suitable for High-Frequency PCB?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/#What_Applications_Commonly_Use_FR408HR_PCB_Material\" >What Applications Commonly Use FR408HR PCB Material?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/#What_Affects_FR408HR_PCB_Price\" >What Affects FR408HR PCB Price?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/#What_Are_the_Equivalent_Materials_to_FR408HR\" >What Are the Equivalent Materials to FR408HR?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-14\" href=\"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/#Why_Choose_EBest_Circuit_as_Your_FR408HR_PCB_Manufacturer\" >Why Choose EBest Circuit as Your FR408HR PCB Manufacturer?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-15\" href=\"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/#FAQs_About_FR408HR_PCB_Material\" >FAQs About FR408HR PCB Material<\/a><\/li><\/ul><\/nav><\/div>\n<div class=\"yzp-no-index\"><\/div>\n<p><strong><a href=\"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/\" title=\"\">FR408HR<\/a><\/strong> is a high-performance PCB laminate for high-speed projects that require <strong>stable Dk, low Df, high Tg, controlled impedance and reliable lead-free assembly<\/strong>. It is often selected when standard FR4 cannot provide enough signal integrity or thermal stability for multilayer PCB fabrication.<\/p>\n\n\n\n<p>This guide explains FR408HR from a practical manufacturing view, including <strong>material properties, datasheet values, thickness options, FR4 comparison, 370HR and Rogers 4350B selection, application areas, price factors and sourcing advice<\/strong> for custom high-speed PCB projects.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full is-resized\"><a href=\"https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR408HR.png\"><img loading=\"lazy\" decoding=\"async\" width=\"921\" height=\"517\" src=\"https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR408HR.png\" alt=\"FR408HR, https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/\" class=\"wp-image-29519\" style=\"aspect-ratio:3\/2;object-fit:contain;width:800px\" srcset=\"https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR408HR.png 921w, https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR408HR-300x168.png 300w, https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR408HR-768x431.png 768w\" sizes=\"auto, (max-width: 921px) 100vw, 921px\" \/><\/a><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"What_Is_FR408HR_PCB_Material\"><\/span>What Is FR408HR PCB Material?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p><strong><a href=\"https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/\" title=\"\">FR408HR PCB material <\/a><\/strong>is a <strong>high-performance FR-4 laminate and prepreg system<\/strong> from Isola. It is used for multilayer PCB applications that require <strong>better thermal and electrical stability<\/strong> than common FR4.<\/p>\n\n\n\n<p>The laminate uses a multifunctional resin system with electrical-grade E-glass fabric. It can be processed with familiar FR4 manufacturing methods while offering <strong>better signal performance, stronger lead-free assembly reliability and improved resistance to thermal stress<\/strong>.<\/p>\n\n\n\n<p>In real PCB production, this material is not an ultra-low-loss RF laminate. It is a balanced option for <strong>high-speed digital PCB, dense multilayer PCB, controlled impedance PCB and reliable electronic products<\/strong>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Why_Is_Isola_FR408HR_Used_for_High-Speed_PCB_Design\"><\/span>Why Is Isola FR408HR Used for High-Speed PCB Design?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>Isola FR408HR is used in high-speed PCB design because it provides <strong>lower dielectric loss, stable Dk, high Tg and good multilayer process compatibility<\/strong>. These features help reduce signal attenuation and improve assembly reliability.<\/p>\n\n\n\n<p>Key reasons include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Lower Df<\/strong> reduces insertion loss on high-speed traces.<\/li>\n\n\n\n<li><strong>Stable Dk<\/strong> supports controlled impedance routing.<\/li>\n\n\n\n<li><strong>High Tg<\/strong> improves lead-free reflow reliability.<\/li>\n\n\n\n<li><strong>Strong thermal stability<\/strong> reduces delamination risk.<\/li>\n\n\n\n<li><strong>CAF resistance<\/strong> supports fine spacing and dense routing.<\/li>\n\n\n\n<li><strong>FR4-like processing<\/strong> helps control manufacturing cost.<\/li>\n<\/ul>\n\n\n\n<p>As a result, this Isola laminate is common in <strong>networking hardware, communication equipment, industrial control, medical electronics and high-speed computing products<\/strong>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"What_Is_the_Dielectric_Constant_and_Dk_Value_of_FR408HR\"><\/span>What Is the Dielectric Constant and Dk Value of FR408HR?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>The FR408HR dielectric constant, also called Dk, is commonly listed around <strong>3.68<\/strong>. This value affects <strong>impedance, signal propagation speed and trace geometry<\/strong>, so it is critical for high-speed PCB design.<\/p>\n\n\n\n<p>However, Dk is not identical in every construction. It changes with <strong>frequency, resin content, glass style, dielectric spacing and copper roughness<\/strong>. For controlled impedance PCB, the correct value should come from the selected core and prepreg structure.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><strong>Frequency<\/strong><\/th><th><strong>Dk<\/strong><\/th><\/tr><\/thead><tbody><tr><td>100 MHz<\/td><td>3.72<\/td><\/tr><tr><td>1 GHz<\/td><td>3.69<\/td><\/tr><tr><td>2 GHz<\/td><td>3.68<\/td><\/tr><tr><td>5 GHz<\/td><td>3.64<\/td><\/tr><tr><td>10 GHz<\/td><td>3.65<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>For stable impedance, <strong>confirm the stackup with the PCB manufacturer before layout release<\/strong>. This prevents impedance deviation after fabrication.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"What_Is_the_Loss_Tangent_and_Df_Value_of_FR408HR\"><\/span>What Is the Loss Tangent and Df Value of FR408HR?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>The FR408HR loss tangent, also called Df value, is commonly listed around <strong>0.0092<\/strong>. Df measures dielectric loss, which directly affects <strong>insertion loss and signal attenuation<\/strong> on high-speed traces.<\/p>\n\n\n\n<p>A lower Df helps the signal travel farther with less energy loss. This is important for <strong>differential pairs, long routing paths, fast edge rates and multilayer designs with controlled impedance<\/strong>.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><strong>Frequency<\/strong><\/th><th><strong>Df<\/strong><\/th><\/tr><\/thead><tbody><tr><td>100 MHz<\/td><td>0.0072<\/td><\/tr><tr><td>1 GHz<\/td><td>0.0091<\/td><\/tr><tr><td>2 GHz<\/td><td>0.0092<\/td><\/tr><tr><td>5 GHz<\/td><td>0.0098<\/td><\/tr><tr><td>10 GHz<\/td><td>0.0095<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>Compared with many standard FR4 grades, this laminate gives <strong>better high-speed performance<\/strong>. For strict RF, microwave or very long channel designs, <strong>lower-loss materials may still be required<\/strong>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"What_Thickness_Options_Are_Available_for_Isola_FR408HR_PCB_Material\"><\/span>What Thickness Options Are Available for Isola FR408HR PCB Material?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>Isola FR408HR thickness depends on the selected <strong>core, prepreg, resin content, copper weight and final PCB stackup<\/strong>. Common finished board thickness options include <strong>0.8 mm, 1.0 mm, 1.2 mm, 1.6 mm, 2.0 mm and custom multilayer thicknesses<\/strong>.<\/p>\n\n\n\n<p>For high-speed PCB, thickness must support the <strong>target impedance first<\/strong>. Dielectric spacing, reference plane distance, trace width and copper thickness should be calculated before the final stackup is approved.<\/p>\n\n\n\n<p>For mechanical design, thickness also affects <strong>board stiffness, connector fit, warpage and assembly stability<\/strong>. Thin boards may need stronger panel support during SMT assembly, while thick multilayer boards require better lamination and drilling control.<\/p>\n\n\n\n<p>For manufacturing, the PCB factory should confirm <strong>core and prepreg availability before layout finalization<\/strong>. This avoids redesign, impedance mismatch, material delay and uncontrolled stackup substitution.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"FR408HR_Material_Properties_Datasheet_Overview\"><\/span>FR408HR Material Properties &amp; Datasheet Overview<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><strong>Parameter<\/strong><\/th><th><strong>Typical Data<\/strong><\/th><th><strong>Note<\/strong><\/th><\/tr><\/thead><tbody><tr><td>Material type<\/td><td>High-performance FR-4 laminate and prepreg<\/td><td>Lead-free, mid-loss system<\/td><\/tr><tr><td>Resin system<\/td><td>Multifunctional epoxy<\/td><td>Reinforced with E-glass fabric<\/td><\/tr><tr><td>Tg by DSC<\/td><td>190\u00b0C<\/td><td>Thermal transition reference<\/td><\/tr><tr><td>Tg by DMA<\/td><td>230\u00b0C<\/td><td>Dynamic mechanical value<\/td><\/tr><tr><td>Td by TGA<\/td><td>360\u00b0C<\/td><td>5% weight loss<\/td><\/tr><tr><td>T260<\/td><td>60 minutes<\/td><td>Thermal endurance<\/td><\/tr><tr><td>T288<\/td><td>&gt;30 minutes<\/td><td>Lead-free assembly reference<\/td><\/tr><tr><td>Dk @ 2 GHz<\/td><td>3.68<\/td><td>Tested at 56% resin<\/td><\/tr><tr><td>Df @ 2 GHz<\/td><td>0.0092<\/td><td>Tested at 56% resin<\/td><\/tr><tr><td>Thermal conductivity<\/td><td>0.4 W\/m\u00b7K<\/td><td>Heat transfer reference<\/td><\/tr><tr><td>Z-axis CTE before Tg<\/td><td>55 ppm\/\u00b0C<\/td><td>Expansion before Tg<\/td><\/tr><tr><td>Z-axis CTE after Tg<\/td><td>230 ppm\/\u00b0C<\/td><td>Expansion after Tg<\/td><\/tr><tr><td>X\/Y-axis CTE before Tg<\/td><td>16 ppm\/\u00b0C<\/td><td>Dimensional stability<\/td><\/tr><tr><td>X\/Y-axis CTE after Tg<\/td><td>18 ppm\/\u00b0C<\/td><td>Dimensional stability<\/td><\/tr><tr><td>Z-axis expansion<\/td><td>2.8%<\/td><td>50\u00b0C to 260\u00b0C<\/td><\/tr><tr><td>Moisture absorption<\/td><td>0.061%<\/td><td>Reflow reliability factor<\/td><\/tr><tr><td>Dielectric breakdown<\/td><td>&gt;50 kV<\/td><td>Insulation strength<\/td><\/tr><tr><td>Arc resistance<\/td><td>137 seconds<\/td><td>Electrical safety behavior<\/td><\/tr><tr><td>Flammability<\/td><td>UL 94 V-0<\/td><td>Flame rating<\/td><\/tr><tr><td>Max operating temperature<\/td><td>130\u00b0C<\/td><td>UL certification reference<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>These datasheet values help confirm whether the laminate fits the <strong>electrical, thermal, mechanical and assembly requirements<\/strong> of the PCB project. For controlled impedance designs, <strong>Dk and Df should still be checked against the exact glass style, resin content and dielectric thickness<\/strong>. Below are FR408HR datasheet PDF for your reference.<\/p>\n\n\n\n<div class=\"wp-block-file\"><a id=\"wp-block-file--media-e98a1492-09dd-475b-b86a-d2a23cae4db5\" href=\"https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR408HR-EBest-Circuit.pdf\">FR408HR-EBest Circuit<\/a><a href=\"https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR408HR-EBest-Circuit.pdf\" class=\"wp-block-file__button wp-element-button\" download aria-describedby=\"wp-block-file--media-e98a1492-09dd-475b-b86a-d2a23cae4db5\">Download<\/a><\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"FR4_vs_FR408HR_What_Is_the_Difference\"><\/span>FR4 vs FR408HR: What Is the Difference?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>FR4 vs FR408HR is mainly a comparison between <strong>general-purpose PCB material and high-performance high-speed PCB material<\/strong>. Standard FR4 is lower cost and widely available, but its electrical performance is usually weaker at higher frequencies.<\/p>\n\n\n\n<p>This Isola material provides <strong>lower loss, higher thermal reliability and better signal stability<\/strong>. It is more suitable for multilayer PCB, fast digital interfaces, BGA routing and controlled impedance designs.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><strong>Item<\/strong><\/th><th><strong>FR4<\/strong><\/th><th><strong>FR408HR<\/strong><\/th><\/tr><\/thead><tbody><tr><td>Material level<\/td><td>Standard FR4<\/td><td>High-performance FR4<\/td><\/tr><tr><td>Signal loss<\/td><td>Higher<\/td><td>Lower<\/td><\/tr><tr><td>Dk stability<\/td><td>Moderate<\/td><td>Better<\/td><\/tr><tr><td>Tg range<\/td><td>Varies by grade<\/td><td>High Tg<\/td><\/tr><tr><td>High-speed use<\/td><td>Limited<\/td><td>Better<\/td><\/tr><tr><td>Cost<\/td><td>Lower<\/td><td>Higher<\/td><\/tr><tr><td>Best fit<\/td><td>General PCB<\/td><td>High-speed PCB<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>If a PCB has <strong>long high-speed traces, strict impedance control or repeated lead-free reflow stress<\/strong>, the upgraded laminate is usually the better option.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full is-resized\"><a href=\"https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR4-vs-FR408HR-1.png\"><img loading=\"lazy\" decoding=\"async\" width=\"845\" height=\"512\" src=\"https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR4-vs-FR408HR-1.png\" alt=\"FR4 vs FR408HR, https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/\" class=\"wp-image-29533\" style=\"aspect-ratio:3\/2;object-fit:contain;width:800px\" srcset=\"https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR4-vs-FR408HR-1.png 845w, https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR4-vs-FR408HR-1-300x182.png 300w, https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR4-vs-FR408HR-1-768x465.png 768w\" sizes=\"auto, (max-width: 845px) 100vw, 845px\" \/><\/a><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"FR408_vs_FR408HR_vs_FR408HRS_How_Should_You_Choose\"><\/span>FR408 vs FR408HR vs FR408HRS: How Should You Choose?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>FR408, FR408HR and FR408HRS are often searched together because the names look similar. However, they should not be treated as the same material in <strong>quotation, stackup design or procurement<\/strong>.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><strong>Item<\/strong><\/th><th><strong>FR408<\/strong><\/th><th><strong>FR408HR<\/strong><\/th><th><strong>FR408HRS<\/strong><\/th><\/tr><\/thead><tbody><tr><td>Material status<\/td><td>Earlier high-performance FR4 option<\/td><td>Current high-speed and high-reliability choice<\/td><td>Must verify exact material name<\/td><\/tr><tr><td>Main focus<\/td><td>Improved signal performance over standard FR4<\/td><td>Lower loss, higher thermal reliability and lead-free support<\/td><td>Often appears as a search or supplier term<\/td><\/tr><tr><td>Typical use<\/td><td>Older high-speed PCB designs<\/td><td>New high-speed multilayer PCB projects<\/td><td>Only use after written confirmation<\/td><\/tr><tr><td>Tg reference<\/td><td>Lower than HR grade<\/td><td>High Tg grade<\/td><td>Depends on confirmed material<\/td><\/tr><tr><td>Loss performance<\/td><td>Good for its generation<\/td><td>Better balanced for modern high-speed PCB<\/td><td>Cannot assume without datasheet<\/td><\/tr><tr><td>Procurement risk<\/td><td>May be limited by availability<\/td><td>Easier to specify clearly<\/td><td>Higher risk of naming confusion<\/td><\/tr><tr><td>Best choice<\/td><td>Legacy designs or approved old stackups<\/td><td>New designs, controlled impedance and lead-free assembly<\/td><td>Not recommended without material approval<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>For new projects, <strong>FR408HR is usually the safest choice<\/strong> because the material name is clear, the performance data is widely used, and the laminate is suitable for modern multilayer PCB manufacturing.<\/p>\n\n\n\n<p>If \u201cFR408HRS\u201d appears in an old drawing, supplier quote or customer file, <strong>do not approve production by name alone<\/strong>. Confirm the exact laminate, datasheet, Dk, Df, Tg, copper type and approved equivalent list before ordering.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"FR408HR_vs_370HR_Which_Material_Is_Better_for_Your_PCB_Project\"><\/span>FR408HR vs 370HR: Which Material Is Better for Your PCB Project?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>FR408HR vs 370HR depends on whether the project cares more about <strong>signal loss or general thermal reliability<\/strong>. Both are Isola high-reliability materials, but they serve different design priorities.<\/p>\n\n\n\n<p>370HR is often selected for reliable multilayer PCB where <strong>thermal performance and CAF resistance<\/strong> matter. The high-speed laminate is better when the design also has <strong>lower-loss routing, controlled impedance sensitivity and fast digital signals<\/strong>.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><strong>Item<\/strong><\/th><th><strong>370HR<\/strong><\/th><th><strong>FR408HR<\/strong><\/th><\/tr><\/thead><tbody><tr><td>Main focus<\/td><td>Thermal reliability<\/td><td>High-speed performance<\/td><\/tr><tr><td>Dk<\/td><td>Higher<\/td><td>Lower<\/td><\/tr><tr><td>Df<\/td><td>Higher<\/td><td>Lower<\/td><\/tr><tr><td>Best use<\/td><td>Reliable FR4 multilayer PCB<\/td><td>High-speed multilayer PCB<\/td><\/tr><tr><td>Cost<\/td><td>Usually lower<\/td><td>Usually higher<\/td><\/tr><tr><td>Selection logic<\/td><td>Reliability first<\/td><td>Signal integrity first<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>Choose 370HR for <strong>reliability-focused PCB<\/strong>. Choose the lower-loss option when <strong>signal integrity is a clear design priority<\/strong>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"FR408HR_vs_Rogers_4350B_Which_One_Is_Suitable_for_High-Frequency_PCB\"><\/span>FR408HR vs Rogers 4350B: Which One Is Suitable for High-Frequency PCB?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>FR408HR vs <strong><a href=\"https:\/\/www.bestpcbs.com\/blog\/2025\/12\/rogers-ro4350b-datasheet-amp-material-guide-for-rf-pcb\/\" title=\"\">Rogers 4350B <\/a><\/strong>should be decided by <strong>frequency, loss budget, RF performance and cost target<\/strong>. The Isola laminate is suitable for many high-speed digital PCB projects, while Rogers 4350B is better for RF, microwave and lower-loss high-frequency PCB.<\/p>\n\n\n\n<p>The Isola laminate keeps <strong>FR4-like processing and lower cost<\/strong>. Rogers 4350B offers <strong>lower dielectric loss and stronger high-frequency performance<\/strong>, but it usually needs higher material cost and tighter process control.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><strong>Item<\/strong><\/th><th><strong>FR408HR<\/strong><\/th><th><strong>Rogers 4350B<\/strong><\/th><\/tr><\/thead><tbody><tr><td>Material type<\/td><td>High-performance FR4<\/td><td>RF laminate<\/td><\/tr><tr><td>Df level<\/td><td>Mid-loss<\/td><td>Lower loss<\/td><\/tr><tr><td>Best use<\/td><td>High-speed digital PCB<\/td><td>RF and microwave PCB<\/td><\/tr><tr><td>Manufacturing cost<\/td><td>Lower<\/td><td>Higher<\/td><\/tr><tr><td>Process compatibility<\/td><td>Easier<\/td><td>More controlled<\/td><\/tr><tr><td>Project fit<\/td><td>Networking, computing, industrial<\/td><td>Antenna, RF, microwave<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>Use the Isola material for <strong>cost-effective high-speed PCB<\/strong>. Use Rogers 4350B when <strong>RF loss performance is the main requirement<\/strong>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"What_Applications_Commonly_Use_FR408HR_PCB_Material\"><\/span>What Applications Commonly Use FR408HR PCB Material?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>FR408HR PCB material is commonly used in products that need <strong>better signal integrity, stronger thermal reliability and stable multilayer PCB performance<\/strong>. It is especially useful when standard FR4 creates too much signal loss or reliability risk.<\/p>\n\n\n\n<p>Common applications include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>High-speed networking switches and routers.<\/strong><\/li>\n\n\n\n<li><strong>Communication backplanes and line cards.<\/strong><\/li>\n\n\n\n<li><strong>Servers, storage systems and computing hardware.<\/strong><\/li>\n\n\n\n<li><strong>Industrial control PCB and automation equipment.<\/strong><\/li>\n\n\n\n<li><strong>Medical electronics and diagnostic equipment.<\/strong><\/li>\n\n\n\n<li><strong>Aerospace and defense electronics.<\/strong><\/li>\n\n\n\n<li><strong>Test and measurement instruments.<\/strong><\/li>\n\n\n\n<li><strong>High-density BGA PCB and HDI PCB.<\/strong><\/li>\n\n\n\n<li><strong>Controlled impedance PCB with differential pairs.<\/strong><\/li>\n\n\n\n<li><strong>High-speed connector and SERDES routing boards.<\/strong><\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-full is-resized\"><a href=\"https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR408HR-Applications.png\"><img loading=\"lazy\" decoding=\"async\" width=\"881\" height=\"623\" src=\"https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR408HR-Applications.png\" alt=\"FR408HR Applications, https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/\" class=\"wp-image-29538\" style=\"aspect-ratio:3\/2;object-fit:contain;width:800px\" srcset=\"https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR408HR-Applications.png 881w, https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR408HR-Applications-300x212.png 300w, https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR408HR-Applications-768x543.png 768w\" sizes=\"auto, (max-width: 881px) 100vw, 881px\" \/><\/a><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"What_Affects_FR408HR_PCB_Price\"><\/span>What Affects FR408HR PCB Price?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>FR408HR PCB price is affected by <strong>material cost, board structure, stackup complexity, production quantity, testing level and delivery schedule<\/strong>. The fr408hr laminate price per square foot also changes with copper foil, thickness, supplier stock and market availability.<\/p>\n\n\n\n<p>Main cost factors include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Original Isola material or approved equivalent.<\/strong><\/li>\n\n\n\n<li><strong>PCB layer count and final thickness.<\/strong><\/li>\n\n\n\n<li><strong>Core, prepreg and copper weight selection.<\/strong><\/li>\n\n\n\n<li><strong>Controlled impedance tolerance.<\/strong><\/li>\n\n\n\n<li><strong>HDI, blind vias, buried vias or via filling.<\/strong><\/li>\n\n\n\n<li><strong>Back drilling for high-speed signal quality.<\/strong><\/li>\n\n\n\n<li><strong>ENIG, OSP, immersion silver or hard gold finish.<\/strong><\/li>\n\n\n\n<li><strong>IPC Class 2 or Class 3 inspection.<\/strong><\/li>\n\n\n\n<li><strong>Prototype quantity or batch production volume.<\/strong><\/li>\n\n\n\n<li><strong>Urgent delivery and material stock status.<\/strong><\/li>\n<\/ul>\n\n\n\n<p>For an accurate quotation, send <strong>Gerber files, stackup, quantity, surface finish, copper weight, impedance requirements and test standards<\/strong>. Complete files reduce engineering questions and avoid price changes after review.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"What_Are_the_Equivalent_Materials_to_FR408HR\"><\/span>What Are the Equivalent Materials to FR408HR?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>FR408HR equivalent material should be selected by <strong>Dk, Df, Tg, Td, CTE, availability, processing behavior and project risk<\/strong>, not by price alone. A wrong replacement may change impedance, signal loss, lamination behavior or long-term reliability.<\/p>\n\n\n\n<p>Possible comparison options include:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><strong>Material<\/strong><\/th><th><strong>Best Fit<\/strong><\/th><\/tr><\/thead><tbody><tr><td>Isola 370HR<\/td><td>Reliability-focused FR4 multilayer PCB<\/td><\/tr><tr><td>Isola I-Speed<\/td><td>Lower-loss high-speed digital PCB<\/td><\/tr><tr><td>Isola I-Tera MT40<\/td><td>Very low-loss high-speed PCB<\/td><\/tr><tr><td>Panasonic Megtron Series<\/td><td>High-speed and low-loss PCB<\/td><\/tr><tr><td>Rogers 4350B<\/td><td>RF and microwave PCB<\/td><\/tr><tr><td>Nelco N4000 Series<\/td><td>High-speed PCB alternatives<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>Before replacing the material, confirm <strong>signal speed, trace length, RF requirement, thermal stress, budget and material availability<\/strong>. Stackup and impedance should also be reviewed again.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Why_Choose_EBest_Circuit_as_Your_FR408HR_PCB_Manufacturer\"><\/span>Why Choose EBest Circuit as Your FR408HR PCB Manufacturer?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>EBest Circuit supports custom high-speed PCB projects from prototype to batch production. Our value is simple: <strong>stable material control, clear engineering review, reliable production and global delivery from a China-based direct PCB factory<\/strong>.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Reduce material risk:<\/strong> We confirm material brand, stackup, copper weight and approved equivalent options before production.<\/li>\n\n\n\n<li><strong>Improve signal reliability:<\/strong> Controlled impedance review, impedance coupon support and stackup checking help reduce signal deviation.<\/li>\n\n\n\n<li><strong>Support complex PCB builds:<\/strong> We can support multilayer PCB, HDI PCB, BGA PCB, blind vias, buried vias, via filling and back drilling.<\/li>\n\n\n\n<li><strong>Strengthen assembly quality:<\/strong> SMT assembly, BGA assembly, X-ray inspection and solderability checks support reliable PCBA delivery.<\/li>\n\n\n\n<li><strong>Control batch consistency:<\/strong> AOI, electrical test, microsection, impedance testing and final inspection help reduce quality variation.<\/li>\n\n\n\n<li><strong>Simplify global sourcing:<\/strong> Clear English communication, export-ready documents and RoHS-compliant packaging make overseas purchasing easier.<\/li>\n\n\n\n<li><strong>Support OEM\/ODM projects:<\/strong> Prototype, engineering verification and batch production can be matched to different project stages.<\/li>\n<\/ul>\n\n\n\n<p>If your project requires reliable FR408HR PCB fabrication or PCBA assembly, EBest Circuit can review your files and provide a clear project-based quotation.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR408HR-PCB.png\"><img loading=\"lazy\" decoding=\"async\" width=\"926\" height=\"555\" src=\"https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR408HR-PCB.png\" alt=\"FR408HR PCB, https:\/\/www.bestpcbs.com\/blog\/2026\/07\/fr408hr\/\" class=\"wp-image-29550\" srcset=\"https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR408HR-PCB.png 926w, https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR408HR-PCB-300x180.png 300w, https:\/\/www.bestpcbs.com\/blog\/wp-content\/uploads\/2026\/07\/FR408HR-PCB-768x460.png 768w\" sizes=\"auto, (max-width: 926px) 100vw, 926px\" \/><\/a><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"FAQs_About_FR408HR_PCB_Material\"><\/span>FAQs About FR408HR PCB Material<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p><strong>Q1. Does copper roughness affect signal loss on this laminate?<\/strong><br>A1. <strong>Yes. Copper roughness can increase conductor loss, especially on high-speed traces.<\/strong> Even with a stable dielectric material, rough copper may reduce signal quality. For this reason, high-speed PCB projects should review <strong>copper foil type, trace length, impedance target and insertion loss budget<\/strong> before production.<\/p>\n\n\n\n<p><strong>Q2. What impedance tolerance is realistic for high-speed PCB?<\/strong><br>A2. <strong>Common controlled impedance tolerance is often around \u00b110%, while tighter tolerance may be possible depending on design and factory capability. <\/strong>The final result depends on <strong>dielectric thickness, copper thickness, etching control, resin content and test coupon design<\/strong>. Confirm tolerance during stackup review, not after PCB fabrication.<\/p>\n\n\n\n<p><strong>Q3. Can this material support HDI PCB designs?<\/strong><br>A3. <strong>Yes. The laminate can be used in HDI PCB projects when laser drilling, via filling and lamination are properly controlled.<\/strong> For dense BGA routing, the factory should review <strong>microvia structure, dielectric thickness, copper balance and lamination cycles<\/strong> before confirming production feasibility.<\/p>\n\n\n\n<p><strong>Q4. How can material authenticity be verified?<\/strong><br>A4. <strong>Request material confirmation before production. <\/strong>For high-reliability projects, ask for <strong>material brand, laminate type, date code, certificate of conformity and traceability record<\/strong>. This reduces the risk of wrong substitutes, unstable Dk values and batch quality issues.<\/p>\n\n\n\n<p><strong>Q5. Is this laminate suitable for BGA assembly?<\/strong><br>A5.<strong> Yes. It is suitable for BGA PCB when pad design, solder mask registration, board flatness and surface finish are controlled. <\/strong>ENIG is often selected for fine-pitch BGA because it provides flat pads and stable solderability. For reliable assembly, <strong>X-ray inspection is recommended after reflow<\/strong>.<\/p>\n\n\n\n<p><strong>Q6. Can this laminate be mixed with other materials in one stackup?<\/strong><br>A6. <strong>Mixed-material stackups are possible, but they require careful engineering review. Different laminates may have different Dk, Df, CTE and lamination behavior. <\/strong>Before approval, check <strong>bonding compatibility, impedance shift, thermal stress, material availability and production repeatability<\/strong>.<\/p>\n\n\n\n<p><strong>Q7. What surface finish is commonly used for this type of PCB?<\/strong><br>A7. <strong>ENIG is commonly used because it provides flat pads, good solderability and strong support for BGA assembly. <\/strong>OSP may be selected for cost-sensitive projects, while immersion silver can be used in some signal-sensitive applications. The best finish depends on <strong>assembly method, storage time, pad design and reliability target<\/strong>.<\/p>\n\n\n\n<p><strong>Q8. Does this laminate support lead-free assembly?<\/strong><br>A8. <strong>Yes. It is designed for lead-free PCB assembly and can handle high-temperature reflow better than many common FR4 materials.<\/strong> However, reliable assembly still depends on <strong>correct baking, storage, soldering profile and process control<\/strong>. Moisture control is especially important for multilayer PCB and BGA assembly.<\/p>\n\n\n\n<p><strong>Q9. What files are required for an accurate quotation?<\/strong><br>A9. <strong>Provide Gerber files, drill files, stackup, board thickness, copper weight, surface finish, impedance requirements, quantity and test requirements.<\/strong> For PCBA orders, also provide BOM, pick-and-place files and assembly drawings. Complete files help calculate cost accurately and reduce engineering delays.<\/p>\n\n\n\n<p><strong>Q10. How can wrong material substitution be avoided?<\/strong><br>A10. <strong>Clearly state Isola FR408HR or approved equivalent in the PCB specification. Also request material confirmation and traceability records when needed.<\/strong> For high-reliability projects, material approval should happen <strong>before production, not after delivery<\/strong>. This helps avoid wrong laminate, wrong Dk and unstable PCB performance.<\/p>\n\n\n\n<p><strong>Q11. Is this material suitable for both prototype and mass production?<\/strong><br>A11. <strong>Yes. It can be used for prototype and mass production. <\/strong>For prototypes, <strong>material stock and stackup confirmation<\/strong> are the main lead-time factors. For mass production, <strong>stable sourcing, impedance control, lamination consistency, electrical testing and inspection records<\/strong> become more important.<\/p>\n\n\n\n<p><strong>Q12. What inspection methods are useful for high-speed PCB?<\/strong><br>A12. <strong>Useful inspection methods include AOI, electrical testing, impedance testing, microsection analysis, solderability inspection and final dimensional inspection.<\/strong> For assembled boards, <strong>BGA X-ray and functional testing<\/strong> may also be required. These checks help confirm circuit accuracy, plating quality, impedance control and assembly reliability.<\/p>\n\n\n\n<p><strong>Q13. When should a lower-loss material be selected instead?<\/strong><br>A13.<strong> Choose a lower-loss laminate when the design has very long channels, strict insertion loss limits, RF circuits, microwave signals or high-frequency antenna sections<\/strong>. In these cases, Rogers, I-Tera, Megtron or other low-loss materials may provide better performance than a mid-loss high-speed FR4 laminate.<\/p>\n\n\n\n<p><strong>Q14. What should be checked before approving production?<\/strong><br>A14. <strong>Before production, confirm material name, stackup, copper weight, board thickness, impedance tolerance, via structure, surface finish, IPC class, testing method and delivery schedule<\/strong>. This review helps avoid redesign, wrong material use, impedance failure, assembly risk and unexpected cost increases.<\/p>\n\n\n\n<p><strong>Conclusion<\/strong><\/p>\n\n\n\n<p>FR408HR is a strong option for high-speed multilayer PCB when standard FR4 cannot provide enough <strong>signal integrity, thermal stability or lead-free assembly reliability<\/strong>. Its key value is <strong>stable Dk, low Df, high Tg, controlled impedance support and FR4-compatible processing<\/strong>.<\/p>\n\n\n\n<p>For selection, use this material for <strong>high-speed digital PCB, controlled impedance PCB, networking equipment, industrial control, medical electronics, dense BGA boards and reliable multilayer products<\/strong>. Choose 370HR when thermal reliability and cost are the main concerns. Choose Rogers 4350B or other low-loss laminates when RF, microwave or strict insertion loss performance is required.<\/p>\n\n\n\n<p>For procurement, confirm the exact <strong>laminate, stackup, copper weight, surface finish, impedance tolerance, inspection standard and delivery schedule<\/strong> before production. <strong><a href=\"https:\/\/www.bestpcbs.com\/\" title=\"\">EBest Circuit <\/a><\/strong>supports <strong><a href=\"https:\/\/www.bestpcbs.com\/products\/high-speed-pcb.htm\" title=\"\">high speed PCB<\/a> fabrication, PCBA assembly, stackup review, impedance control, prototype builds and batch production<\/strong> from our China-based direct PCB factory. Send your Gerber files and project requirements to <strong><a href=\"mailto:sales@bestpcbs.com\">sales@bestpcbs.com<\/a><\/strong> for a fast quotation.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>FR408HR is a high-performance PCB laminate for high-speed projects that require stable Dk, low Df, high Tg, controlled impedance and reliable lead-free assembly. It is often selected when standard FR4 cannot provide enough signal integrity or thermal stability for multilayer PCB fabrication. This guide explains FR408HR from a practical manufacturing view, including material properties, datasheet [&hellip;]<\/p>\n","protected":false},"author":33247,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_uf_show_specific_survey":0,"_uf_disable_surveys":false,"footnotes":""},"categories":[175,174,5309],"tags":[6549,6552,6550,6553,6551],"class_list":["post-29457","post","type-post","status-publish","format-standard","hentry","category-best-pcb","category-bestpcb","category-pcb-material","tag-fr408hr-datasheet","tag-fr408hr-dielectric-constant","tag-fr408hr-pcb","tag-fr408hr-price","tag-fr408hr-vs-370hr"],"acf":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.bestpcbs.com\/blog\/wp-json\/wp\/v2\/posts\/29457","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.bestpcbs.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.bestpcbs.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.bestpcbs.com\/blog\/wp-json\/wp\/v2\/users\/33247"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bestpcbs.com\/blog\/wp-json\/wp\/v2\/comments?post=29457"}],"version-history":[{"count":13,"href":"https:\/\/www.bestpcbs.com\/blog\/wp-json\/wp\/v2\/posts\/29457\/revisions"}],"predecessor-version":[{"id":29551,"href":"https:\/\/www.bestpcbs.com\/blog\/wp-json\/wp\/v2\/posts\/29457\/revisions\/29551"}],"wp:attachment":[{"href":"https:\/\/www.bestpcbs.com\/blog\/wp-json\/wp\/v2\/media?parent=29457"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bestpcbs.com\/blog\/wp-json\/wp\/v2\/categories?post=29457"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bestpcbs.com\/blog\/wp-json\/wp\/v2\/tags?post=29457"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}