{"id":64499,"date":"2025-05-12T09:52:19","date_gmt":"2025-05-12T06:52:19","guid":{"rendered":"https:\/\/wpcalc.com\/en\/?p=64499"},"modified":"2025-05-12T09:53:08","modified_gmt":"2025-05-12T06:53:08","slug":"microstrip-pcb-impedance","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/engineering\/microstrip-pcb-impedance\/","title":{"rendered":"Microstrip PCB Impedance Calculator"},"content":{"rendered":"<section class=\"not-prose calculator-box\" aria-labelledby=\"calculator-title\"><div class=\"flex items-baseline sm:items-center justify-between gap-2 sm:gap-3\"><div class=\"flex flex-col sm:flex-row sm:items-center gap-2\"><span class=\"icon icon-calculator text-primary-700! text-base! dark:text-primary-300!\" aria-hidden=\"true\"><\/span><h2 class=\"text-lg font-display font-bold\">PCB Trace Impedance Estimator<\/h2><\/div><div class=\"relative group inline-block\">\n  <button class=\"favorite\" id=\"favorite\" data-favorite-id=\"64499\" data-favorite-title=\"Microstrip PCB Impedance\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/engineering\/microstrip-pcb-impedance\/\" data-favorite-excerpt=\"This calculator determines the characteristic impedance of a microstrip trace on a PCB based on its width, substrate height, and dielectric constant. It is crucial for maintaining signal integrity in high-speed digital and RF PCB designs.\" aria-label=\"Add to Favorites\" data-favorite-icon=\"icon icon-electrical\">\n    <span class=\"icon icon-shape-star-empty\"><\/span>\n  <\/button>\n  <div class=\"absolute right-full -translate-y-1\/2 top-1\/2 mr-2 w-max max-w-xs px-3 py-2 bg-gray-800 text-white text-xs rounded shadow-lg opacity-0 group-hover:opacity-100 transition-opacity duration-200 z-10 pointer-events-none\">\n   <span class=\"favorite-tooltip\" id=\"favorite-tooltip\"><\/span>\n  <\/div>\n<\/div><\/div><form action=\"https:\/\/wpcalc.com\/en\/engineering\/microstrip-pcb-impedance\/\" method=\"POST\" class=\"calculator\" id=\"calculator-64499\" data-post=\"64499\"><fieldset class=\"fieldset-input\"><legend class=\"sr-only\">Input Fields<\/legend><div class=\"field has-term\" id=\"input-1\"><label for=\"field-1\">Dielectric constant (\u03b5r)<\/label><div class=\"term\">\u03b5\u1d63<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"number\" name=\"dielectric_constant_r\" id=\"field-1\" min=\"1\" step=\"0.01\" value=\"4.5\"\/><small>Relative permittivity of PCB substrate<\/small><\/div><div class=\"field has-term\" id=\"input-2\"><label for=\"field-2\">Trace width (W)<\/label><div class=\"term\">W<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"number\" name=\"trace_width_w\" id=\"field-2\" min=\"0.01\" step=\"0.01\" value=\"1\"\/><div class=\"unit\">mm<\/div><small>Width of the microstrip trace<\/small><\/div><div class=\"field has-term\" id=\"input-3\"><label for=\"field-3\">Substrate height (H)<\/label><div class=\"term\">H<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"number\" name=\"substrate_height_h\" id=\"field-3\" min=\"0.01\" step=\"0.01\" value=\"1.6\"\/><div class=\"unit\">mm<\/div><small>Height from trace to ground plane<\/small><\/div><div class=\"field has-term\" id=\"input-4\"><label for=\"field-4\">Copper thickness (T)<\/label><div class=\"term\">T<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"number\" name=\"copper_thickness_t\" id=\"field-4\" min=\"0\" step=\"0.001\" value=\"0.035\"\/><div class=\"unit\">mm<\/div><small>Thickness of the copper trace<\/small><\/div><\/fieldset><div class=\"buttons\"><button type=\"submit\" data-text=\"Re-Calculate\" id=\"calculate-button\" data-post=\"64499\">Calculate<\/button><button type=\"reset\">Reset<\/button><\/div><div class=\"field is-checkbox hidden!\" id=\"field-auto-calc\"><input type=\"checkbox\" id=\"auto-calc\"><label for=\"auto-calc\">Calculate automatically<\/label><small>If enabled, the result will update automatically when you change any value.<\/small><\/div><div class=\"fieldset-result is-hidden\" aria-labelledby=\"result-title\" aria-live=\"polite\" role=\"region\"> <h3 class=\"result-title bg-gradient-to-r from-primary-50 to-gray-50 dark:from-primary-900 dark:to-gray-800\" id=\"result-title\"><span class=\"icon icon-s-pulse\" aria-hidden=\"true\"><\/span> Your Results<\/h3><div class=\"result-box\"><div class=\"field-result\" id=\"output-1\"><span class=\"field-title\"><span>Characteristic Impedance<\/span><\/span><span class=\"field-value\" id=\"result-1\" data-unit=\"\u03a9\"><\/span><button class=\"copy-result\" data-tooltip=\"Copy Result\"><span class=\"copy-icon icon icon-document-copy\"><\/span><\/button><\/div><\/div><\/div><a href=\"#respond\" class=\"hidden transition-opacity duration-300 opacity-0 w-50 text-sm justify-center items-center gap-2 px-4 py-2 rounded bg-gray-200 text-gray-700 hover:bg-gray-300\" id=\"leave-comment\"><span class=\"icon icon-comments\" aria-hidden=\"true\"><\/span>Leave a Comment<\/a><\/form><\/section><section id=\"calc-reactions\" class=\"not-prose hidden my-12 bg-gradient-to-r from-primary-50 to-gray-50 border border-indigo-100 rounded-xl px-6 py-4 shadow-sm\" data-post=\"64499\" aria-live=\"polite\"><h2 class=\"text-sm text-gray-500 text-center mb-2\">How did this result make you feel?<\/h2><div class=\"grid grid-cols-3 sm:flex sm:flex-row sm:justify-around gap-4 sm:items-center sm:flex-wrap\"><button class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"like\"><span class=\"reaction-count\" data-reaction-count=\"like\">0<\/span><span class=\"reaction text-3xl\">\ud83d\ude00 <\/span><span class=\"reaction-description font-medium\">Like <\/span><\/button><button class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"helpful\"><span class=\"reaction-count\" data-reaction-count=\"helpful\">0<\/span><span class=\"reaction text-3xl\">\ud83d\udca1 <\/span><span class=\"reaction-description font-medium\">Helpful <\/span><\/button><button class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"confused\"><span class=\"reaction-count\" data-reaction-count=\"confused\">0<\/span><span class=\"reaction text-3xl\">\ud83d\ude15 <\/span><span class=\"reaction-description font-medium\">Confused <\/span><\/button><button class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"disappointed\"><span class=\"reaction-count\" data-reaction-count=\"disappointed\">0<\/span><span class=\"reaction text-3xl\">\ud83d\ude1e <\/span><span class=\"reaction-description font-medium\">Disappointed <\/span><\/button><button class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"inaccurate\"><span class=\"reaction-count\" data-reaction-count=\"inaccurate\">1<\/span><span class=\"reaction text-3xl\">\u274c <\/span><span class=\"reaction-description font-medium\">Inaccurate <\/span><\/button><\/div><div id=\"reaction-message\" class=\"hidden mt-8 rounded-md border border-primary-100 bg-white\/50 backdrop-blur-sm px-4 py-2 text-sm text-center shadow-sm\"><\/div><\/section><ins class=\"adsbygoogle\"\n     style=\"display:block; text-align:center; margin: 32px 0;\"\n     data-ad-layout=\"in-article\"\n     data-ad-format=\"fluid\"\n     data-ad-client=\"ca-pub-1721569815777345\"\n     data-ad-slot=\"6317458308\"><\/ins>\n<script>\n     (adsbygoogle = window.adsbygoogle || []).push({});\n<\/script>\n<p><section class=\"formula-box\" aria-labelledby=\"formula-title\">\r\n\t<div id=\"formula-title\" class=\"not-prose font-display mb-4\"><span class=\"icon icon-formula\" aria-hidden=\"true\"><\/span><h2>Microstrip Line Impedance Formulas<\/h2><\/div>\r\n\t<figure class=\"not-prose formula\">\r\n\t\t<figcaption class=\"formula-title\">Formula<\/figcaption>\r\n\t\t<div class=\"text-base text-gray-800\" id=\"formula\">\n$$Z_0 =\n\\begin{cases}\n\\frac{60}{\\sqrt{\\varepsilon_r}} \\cdot \\ln\\left( \\frac{8h}{w} + \\frac{w}{4h} \\right), &#038; \\text{if } \\frac{w}{h} \\leq 1 \\\\[1em]\n\\frac{120\\pi}{\\sqrt{\\varepsilon_r} \\cdot \\left( \\frac{w}{h} + 1.393 + 0.667 \\cdot \\ln\\left( \\frac{w}{h} + 1.444 \\right) \\right)}, &#038; \\text{if } \\frac{w}{h} > 1\n\\end{cases}$$\n<\/div>\r\n\t<\/figure>\r\n\t<br \/>\n<strong>Where:<\/strong><\/p>\n<ul>\n<li>$$Z_0$$ = characteristic impedance (\u03a9)  <\/li>\n<li>$$w$$ = trace width (mm)  <\/li>\n<li>$$h$$ = substrate height (mm)   <\/li>\n<li>$$varepsilon_r$$ = elative dielectric constant of the substrate<\/li>\n<\/ul>\n<p>These equations model the impedance of a microstrip trace above a ground plane.<br \/>\r\n<\/section><br \/>\n<section id=\"calculation\" class=\"calculation-box\" aria-labelledby=\"calculation-title\">\r\n\t<div id=\"calculation-title\" class=\"not-prose font-display\"><span class=\"icon icon-unordered-list\" aria-hidden=\"true\"><\/span><h2>Microstrip PCB Impedance \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<\/p>\n<h3>Given:<\/h3>\n<ul>\n<li>$$w$$ = 0.75 mm    <\/li>\n<li>$$h$$ = 0.6 mm   <\/li>\n<li>$$varepsilon_r$$ = 4.2<\/li>\n<\/ul>\n<h3>Calculation:<\/h3>\n<ol>\n<li>$$\\frac{w}{h} = \\frac{0.75}{0.6} = 1.25 > 1 \\Rightarrow \\text{Use second formula}$$<\/li>\n<li>$$Z_0 = \\frac{120\\pi}{\\sqrt{4.2} \\cdot \\left(1.25 + 1.393 + 0.667 \\cdot \\ln(1.25 + 1.444)\\right)}$$<\/li>\n<li>$$= \\frac{376.99}{2.049 \\cdot (2.643 + 0.667 \\cdot 0.933)}$$<\/li>\n<li>$$= \\frac{376.99}{2.049 \\cdot 3.266} \u2248 \\frac{376.99}{6.693} \u2248 56.32~\\Omega$$<\/li>\n<\/ol>\n<p>\n\r\n<\/section><br \/>\nAccurate calculation of microstrip impedance is essential for PCB designers working with high-speed signals like USB, HDMI, or RF traces. This calculator allows engineers to estimate impedance quickly and optimize trace width for a given substrate height and material. Proper impedance control reduces signal reflection, distortion, and EMI, ensuring reliable and efficient signal transmission in complex circuits.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>This calculator determines the characteristic impedance of a microstrip trace on a PCB based on its width, substrate height, and dielectric constant. It is crucial for maintaining signal integrity in high-speed digital and RF PCB designs.<\/p>\n","protected":false},"author":70,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[4],"tags":[21],"class_list":["post-64499","post","type-post","status-publish","format-standard","hentry","category-engineering","tag-electrical"],"acf":[],"_links":{"self":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/64499","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/users\/70"}],"replies":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/comments?post=64499"}],"version-history":[{"count":3,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/64499\/revisions"}],"predecessor-version":[{"id":64502,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/64499\/revisions\/64502"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=64499"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=64499"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=64499"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}