{"id":13350,"date":"2026-09-26T11:06:19","date_gmt":"2026-09-26T03:06:19","guid":{"rendered":"https:\/\/www.jingpengpcb.com\/?p=13350"},"modified":"2026-10-02T19:45:59","modified_gmt":"2026-10-02T11:45:59","slug":"how-to-choose-pcb-material","status":"publish","type":"post","link":"https:\/\/www.jingpengpcb.com\/en\/blog\/how-to-choose-pcb-material\/","title":{"rendered":"How to Choose the Right PCB Material Based on PCB Type"},"content":{"rendered":"<style>\n.jp-tw{overflow-x:auto;margin:26px 0;-webkit-overflow-scrolling:touch;}\n.jp-tw table{border-collapse:collapse;width:100%;min-width:560px;font-size:15px;line-height:1.65;background:#fff;}\n.jp-tw th,.jp-tw td{border:1px solid #dde3ea;padding:11px 14px;text-align:left;vertical-align:top;}\n.jp-tw thead th{background:#eef2f7;color:#1b2733;font-weight:700;white-space:nowrap;border-bottom:2px solid #c9d3de;}\n.jp-tw tbody tr:nth-child(even){background:#fafbfc;}\n.jp-tw tbody tr:hover{background:#f1f5fa;}\n.jp-tw tbody td:first-child{font-weight:600;color:#1b2733;}\n@media(max-width:767px){.jp-tw table{font-size:14px;min-width:520px;}.jp-tw th,.jp-tw td{padding:9px 11px;}}\n<\/style>\n<p>When selecting PCB materials, the two most common mistakes are: choosing high-frequency materials for a standard industrial control board, which ends up costing three times as much; or manufacturing a 2.4 GHz RF board using standard FR-4 material, resulting in insertion loss exceeding the limit and the entire board being scrapped. The root cause of both is the same\u2014<strong>Instead of first determining the board requirements based on the PCB type, decisions are made based on experience or price.<\/strong>\u3002<\/p>\n<p>This article breaks down the selection process into actionable steps, following the sequence: \u201dFirst, determine the board type \u2192 Then, identify the key parameters \u2192 Finally, make a selection from the list of candidate boards.\u201d<\/p>\n<h2>Step 1: First, identify the five key parameters<\/h2>\n<p>Regardless of the type of panel, its performance ultimately comes down to five parameters. Once you understand these five, you\u2019ll have a consistent standard for selecting the right product.<\/p>\n<h3>1. Tg (glass transition temperature)<\/h3>\n<p>The temperature at which the substrate transitions from a rigid state to a rubbery state. Once Tg is exceeded, the Z-axis coefficient of expansion of the board suddenly increases, causing a corresponding decrease in the reliability of through-holes in multilayer boards. Conventional FR-4 has a Tg of 130\u2013140 \u00b0C, medium-Tg FR-4 has a Tg of approximately 150 \u00b0C, and high-Tg FR-4 can reach 170 \u00b0C or higher. For boards requiring lead-free soldering (peak temperature approximately 245\u2013260 \u00b0C) or secondary reflow, a Tg of at least 150 \u00b0C is recommended.<\/p>\n<h3>2. Dk (Dielectric Constant)<\/h3>\n<p>It determines the signal propagation speed and characteristic impedance. The key point is that the lower the Dk, the lower the signal delay; however, what is even more important is<strong>Stability of Dk<\/strong>\u2014Drift across different batches and at different frequencies directly causes impedance variation. Standard FR-4 has an impedance of approximately 4.2\u20134.7 at 1 GHz, while high-frequency-specific laminates can achieve 2.2\u20133.5 with a gradual change across frequencies.<\/p>\n<h3>3. Df (Dielectric Loss Factor)<\/h3>\n<p>This is the most critical factor in determining high-frequency signal transmission loss and is the most important parameter when selecting high-frequency circuit boards. The categories are roughly as follows:<\/p>\n<div class=\"jp-tw\">\n<table>\n<thead>\n<tr>\n<th>Loss Class<\/th>\n<th>Typical Df value<\/th>\n<th>Applicable Frequency Scenarios<\/th>\n<th>Cost Multiple (relative to standard FR-4)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Ordinary Losses<\/td>\n<td>Approximately 0.020<\/td>\n<td>Below 1 GHz, Digital Circuits<\/td>\n<td>1\u00d7<\/td>\n<\/tr>\n<tr>\n<td>Central Losses<\/td>\n<td>Approximately 0.010<\/td>\n<td>1\u20133 GHz<\/td>\n<td>Approximately 1.5\u20132\u00d7<\/td>\n<\/tr>\n<tr>\n<td>Low loss<\/td>\n<td>0.005 \u2013 0.008<\/td>\n<td>3\u201310 GHz<\/td>\n<td>Approx. 3\u20135\u00d7<\/td>\n<\/tr>\n<tr>\n<td>Ultra-low loss<\/td>\n<td>0.002 \u2013 0.004<\/td>\n<td>10 GHz and above, phased array<\/td>\n<td>Approx. 6\u201310\u00d7<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>Keep this cost multiplier in mind: Replacing the entire board with ultra-low-loss material often comes at a cost that exceeds the budget. A reasonable approach is to<strong>Mixed-voltage<\/strong>\u2014Use high-frequency materials only on the layer containing the RF traces; use standard FR-4 on all other layers.<\/p>\n<h3>4. CTI (Comparative Tracking Index)<\/h3>\n<p>Measuring a material\u2019s resistance to tracking on its surface is critical to long-term insulation reliability under high voltage. Standard FR-4 typically falls within the 175\u2013250 V range, while applications such as high-voltage power supplies and electronic control systems for new energy vehicles require specialized boards with a CTI of \u2265 600 V. This parameter is a mandatory requirement in safety certifications and cannot be compensated for through subsequent processing steps.<\/p>\n<h3>5. Thermal Conductivity<\/h3>\n<p>Standard FR-4 has a thermal conductivity of only about 0.3 W\/(m\u00b7K), so it has virtually no heat dissipation capability. In applications requiring heat dissipation, engineers must either use a metal substrate (with thermal interface layers typically rated at 1.0, 1.5, 2.0, or 3.0 W\/(m\u00b7K)) or incorporate buried copper blocks and arrays of heat-dissipating vias into the FR-4 board.<\/p>\n<h2>Step 2: Select Materials Based on Panel Type<\/h2>\n<p>The table below is the core of this article; it directly lists the board orientation by PCB type.<\/p>\n<div class=\"jp-tw\">\n<table>\n<thead>\n<tr>\n<th>PCB Type<\/th>\n<th>Recommended Substrate Options<\/th>\n<th>Parameters That Must Be Locked<\/th>\n<th>Common Pitfalls<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Standard Rigid Boards (Consumer, Industrial)<\/td>\n<td>Standard FR-4, Tg 130\u2013150 \u00b0C<\/td>\n<td>Tg, board thickness tolerance, copper thickness<\/td>\n<td>A lead-free process was chosen with a Tg of 130 \u00b0C, resulting in delamination after reflow.<\/td>\n<\/tr>\n<tr>\n<td>HDI (High-Density Interconnect) Board<\/td>\n<td>High-Tg FR-4 or specialized HDI boards, combined with a photosensitive dielectric layer<\/td>\n<td>Tg \u2265 150 \u00b0C, Z-axis expansion, microporous reliability<\/td>\n<td>When using standard FR-4 to create blind vias of the second order or higher, the via walls crack after lamination.<\/td>\n<\/tr>\n<tr>\n<td>High-Frequency Microwave Boards<\/td>\n<td>Hydrocarbon Resins \/ PTFE Series (such as Rogers RO4350B, RO4003C, and similar materials)<\/td>\n<td>Dk and Df, Dk Batch Consistency, Mixed-Voltage Compatibility<\/td>\n<td>If only Dk is considered and Df is ignored, insertion loss will exceed the limit; or using high-frequency material for the entire board will cause costs to spiral out of control.<\/td>\n<\/tr>\n<tr>\n<td>Metal Substrates (Aluminum-Based \/ Copper-Based)<\/td>\n<td>Aluminum-based + thermal interface layer, or thermally decoupled copper-based<\/td>\n<td>Thermal conductivity of the dielectric layer, dielectric strength (typically 2\u20134 kV), peel strength<\/td>\n<td>The thermal conductivity of the dielectric layer was set too low, resulting in LED lumen depreciation exceeding the limit.<\/td>\n<\/tr>\n<tr>\n<td>FPC Flexible Circuit Board<\/td>\n<td>Polyimide (PI) substrate + cover film, adhesive-based \/ adhesive-free<\/td>\n<td>PI thickness (typically 12.5, 25, or 50 \u03bcm), number of bends, temperature resistance<\/td>\n<td>Adhesive-based materials were used in dynamic bending applications, but the bending endurance did not meet the required standards.<\/td>\n<\/tr>\n<tr>\n<td>Flex-Rigid Boards<\/td>\n<td>When laminating PI with FR-4 or high-frequency materials, the coefficients of thermal expansion must be matched.<\/td>\n<td>Material CTE matching, lamination window, interlayer alignment<\/td>\n<td>No stress relief was incorporated in the transition zone between the soft and hard sections, resulting in a fracture at the bend.<\/td>\n<\/tr>\n<tr>\n<td>Thick Copper Board<\/td>\n<td>High-Tg FR-4 with thick copper foil<\/td>\n<td>Process Window for Copper Thickness and Line Spacing, Etching Uniformity<\/td>\n<td>Ordered with standard trace spacing; incomplete etching caused a short circuit<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<h2>Step 3: The Three Most Common Mistakes in Product Selection<\/h2>\n<h3>Misconception 1: Treating Tg as the sole indicator<\/h3>\n<p>A high Tg does not necessarily indicate good high-frequency performance or effective heat dissipation. It only addresses thermal stability. Even if a 5 GHz RF board uses FR-4 with a Tg of 180 \u00b0C, its Df will still be on the order of 0.02, and the insertion loss will still exceed the specified limit.<strong>For high-frequency applications, look at Df; for heat dissipation, look at the thermal conductivity; for high-voltage applications, look at CTI; and for heat resistance, look at Tg.<\/strong><\/p>\n<h3>Misconception 2: Ignoring the Process Risks Associated with Mixed-Voltage Design<\/h3>\n<p>Mixed lamination is an effective means of controlling costs; however, the lamination temperature, pressure, and curing time window vary depending on the material, and differences in thermal expansion coefficients can generate internal stress during reflow. Feasible mixed lamination combinations must be validated through process testing and cannot be specified arbitrarily. Before placing an order, you should confirm with the manufacturer whether they have experience with mass production using that specific combination.<\/p>\n<h3>Misconception 3: Specifying only the sheet grade without providing key parameter requirements<\/h3>\n<p>Many purchase orders simply state \u201dUse Rogers 4350\u201d without specifying the board thickness, copper thickness, target DK batch, or impedance requirements. The same grade comes in different thicknesses and copper foil combinations, which can result in significant differences in performance and price. The complete specification should be:<strong>Grade + Thickness + Copper Thickness + Target Values for Key Parameters<\/strong>\u3002<\/p>\n<h2>Step 4: Balance performance, cost, and delivery time<\/h2>\n<p>Three practical constraints need to be considered together:<\/p>\n<ul>\n<li><strong>Cost<\/strong>: The unit price of high-frequency board material may be 3\u201310 times that of standard FR-4; using mixed-layer lamination can limit the cost increase to the RF layers.<\/li>\n<li><strong>Delivery Date<\/strong>: Special sheet materials usually require advance preparation, so standard rush processing options are often not applicable. If a project has a tight deadline, prioritize materials that the factory keeps in stock.<\/li>\n<li><strong>Substitutability<\/strong>: There is a risk of supply disruptions and price increases for imported high-frequency materials; for mass-production projects, it is recommended to identify domestic alternatives in advance and complete their validation.<\/li>\n<\/ul>\n<p>Our recommendation for the prototyping phase is to first conduct a small-batch validation using the target material to confirm that the electrical performance meets specifications before evaluating cost-saving alternatives. This will help avoid choosing the wrong direction during the validation phase simply to save money.<\/p>\n<h2>Step 5: Six Pieces of Information to Prepare Before Submitting a Request<\/h2>\n<p>Clearly specifying the following six items can significantly reduce the time spent on back-and-forth confirmations and ensure a more accurate quote:<\/p>\n<ol>\n<li><strong>Board Types and Application Scenarios<\/strong>(For example: 6-layer HDI, used for the main board of a handheld terminal)<\/li>\n<li><strong>Sheet Material Requirements<\/strong>(Grade or target parameters: Which of the following need to be controlled\u2014Tg, Dk, Df, CTI, or thermal conductivity?)<\/li>\n<li><strong>Stacking Requirements<\/strong>(Number of layers, copper thickness per layer, dielectric thickness; if there are impedance requirements, please include an impedance table)<\/li>\n<li><strong>Process Requirements<\/strong>(Surface treatment, solder mask color, markings, minimum hole diameter, and line width and spacing)<\/li>\n<li><strong>Quantity and Delivery Date<\/strong>(Proof quantity, estimated production run, rush order)<\/li>\n<li><strong>Documents<\/strong>(Gerber RS-274X, drilling files, BOM, and coordinate files, if PCBA is required)<\/li>\n<\/ol>\n<h2>Need help evaluating sheet material options<\/h2>\n<p>Jingpeng Electronics offers expedited PCB prototyping, small- and medium-volume production, and custom HDI boards for complex designs, covering <a href=\"https:\/\/www.jingpengpcb.com\/en\/hdi-pcb\/\">HDI (High-Density Interconnect) Board<\/a>\u3001<a href=\"https:\/\/www.jingpengpcb.com\/en\/high-frequency-pcb\/\">High-Frequency Circuit Boards<\/a>\u3001<a href=\"https:\/\/www.jingpengpcb.com\/en\/metal-substrate\/\">Metal Substrate<\/a>\u3001<a href=\"https:\/\/www.jingpengpcb.com\/en\/flexible-pcb\/\">FPC Flexible Circuit Board<\/a>\u4e0e<a href=\"https:\/\/www.jingpengpcb.com\/en\/rigid-flex-pcb\/\">Flex-Rigid Boards<\/a>, Before accepting an order, our engineering staff will help verify the manufacturability of the sheet metal and the assembly, and provide a delivery schedule and a quote.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-large wp-image-12878\" src=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2026\/01\/pcb-material-warehouse-1024x576.webp\" alt=\"PCB Board Warehouse\" width=\"1024\" height=\"576\" srcset=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2026\/01\/pcb-material-warehouse-1024x576.webp 1024w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2026\/01\/pcb-material-warehouse-300x169.webp 300w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2026\/01\/pcb-material-warehouse-768x432.webp 768w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2026\/01\/pcb-material-warehouse-1536x864.webp 1536w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2026\/01\/pcb-material-warehouse.webp 1920w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/p>\n<p><strong>The specifications listed in this document are industry-standard, publicly available specifications and do not constitute a performance guarantee for any specific model. Actual panel production capacity and inventory are subject to the current status of the production line; please verify with our engineering staff before beginning mass production.<\/strong><\/p>","protected":false},"excerpt":{"rendered":"<p>\u9009\u677f\u6750\u8fd9\u4ef6\u4e8b\uff0c\u6700\u5e38\u89c1\u7684\u4e24\u79cd\u9519\u8bef\u662f\uff1a\u505a\u4e00\u5757\u666e\u901a\u5de5\u63a7\u677f\u5374\u9009\u4e86\u9ad8\u9891\u677f\u6750\uff0c\u767d\u82b1\u4e09\u500d\u4ef7\u94b1\uff1b\u6216\u8005\u505a\u4e00\u5757 2.4 GHz \u5c04 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":12878,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"slim_seo":{"title":"How to Choose the Right PCB Material Based on PCB Type","description":"How do you select PCB materials based on board type? First, we\u2019ll explain five key parameters\u2014Tg, Dk, Df, CTI, and thermal conductivity\u2014and then provide material selection recommendations and highlight common pitfalls for standard boards, high-frequency boards, and metal-core boards."},"_slim_seo_primary_term_category":26,"_slim_seo_primary_term_post_tag":0,"footnotes":""},"categories":[407,26],"tags":[],"class_list":["post-13350","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-pcb-materials","category-blog"],"_links":{"self":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/13350","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/comments?post=13350"}],"version-history":[{"count":2,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/13350\/revisions"}],"predecessor-version":[{"id":13352,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/13350\/revisions\/13352"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/media\/12878"}],"wp:attachment":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/media?parent=13350"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/categories?post=13350"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/tags?post=13350"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}