{"id":64446,"date":"2025-05-12T09:30:45","date_gmt":"2025-05-12T06:30:45","guid":{"rendered":"https:\/\/wpcalc.com\/en\/?p=64446"},"modified":"2025-05-12T09:30:45","modified_gmt":"2025-05-12T06:30:45","slug":"microstrip-transmission-line-impedance","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/engineering\/microstrip-transmission-line-impedance\/","title":{"rendered":"Microstrip Transmission Lines 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\">Microstrip Line Characteristic Impedance Tool<\/h2><\/div><div class=\"relative group inline-block\">\n  <button class=\"favorite\" id=\"favorite\" data-favorite-id=\"64446\" data-favorite-title=\"Microstrip Transmission Lines Impedance\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/engineering\/microstrip-transmission-line-impedance\/\" data-favorite-excerpt=\"This calculator estimates the characteristic impedance of microstrip transmission lines based on trace width, substrate height, and dielectric constant. It\u2019s essential for designing high-speed PCBs and RF circuits where impedance matching is critical.\" 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-transmission-line-impedance\/\" method=\"POST\" class=\"calculator\" id=\"calculator-64446\" data-post=\"64446\"><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<\/label><div class=\"term\">\u03b5r<\/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\" id=\"field-1\" min=\"1\" step=\"0.01\" value=\"4.5\"\/><small>Relative permittivity of the PCB material<\/small><\/div><div class=\"field has-term\" id=\"input-2\"><label for=\"field-2\">Substrate height<\/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\" id=\"field-2\" min=\"0.01\" step=\"0.01\" value=\"1.6\"\/><div class=\"unit\">mm<\/div><small>Height of dielectric layer between trace and ground<\/small><\/div><div class=\"field has-term\" id=\"input-3\"><label for=\"field-3\">Trace width<\/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\" id=\"field-3\" min=\"0.01\" step=\"0.01\" value=\"1\"\/><div class=\"unit\">mm<\/div><small>Width of the transmission line trace<\/small><\/div><div class=\"field has-term\" id=\"input-4\"><label for=\"field-4\">Trace thickness<\/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=\"trace_thickness\" id=\"field-4\" min=\"0\" step=\"0.001\" value=\"0.035\"\/><div class=\"unit\">mm<\/div><small>Copper thickness of the trace<\/small><\/div><\/fieldset><div class=\"buttons\"><button type=\"submit\" data-text=\"Re-Calculate\" id=\"calculate-button\" data-post=\"64446\">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=\"64446\" 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\">0<\/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>Transmission Line Impedance Formula<\/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$$\\text{If } \\frac{w}{h} \\leq 1: \\\\\nZ_0 = \\frac{60}{\\sqrt{\\varepsilon_r}} \\cdot \\ln\\left( \\frac{8h}{w} + \\frac{w}{4h} \\right)\n\\\\[1em]\n\\text{If } \\frac{w}{h} \\geq 1: \\\\\nZ_0 = \\frac{120\\pi}{\\sqrt{\\varepsilon_r} \\cdot \\left( \\frac{w}{h} + 1.393 + 0.667 \\cdot \\ln\\left( \\frac{w}{h} + 1.444 \\right) \\right)}$$\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>$$\\varepsilon_r$$ = dielectric constant<\/li>\n<\/ul>\n<p>These formulas are standard for calculating impedance in microstrip transmission lines with a ground plane beneath.<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 Transmission Lines Impedance \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<p>\n<strong>Given:<\/strong><\/p>\n<ul>\n<li>$$w$$ = 0.9 mm  <\/li>\n<li>$$h$$ = 0.8 mm  <\/li>\n<li>$$\\varepsilon_r$$ = 4.4<\/li>\n<\/ul>\n<p><strong>Calculation:<\/strong><\/p>\n<ol>\n<li>$$\\frac{w}{h} = \\frac{0.9}{0.8} = 1.125 \\Rightarrow \\text{use 2nd formula}$$<\/li>\n<li>$$Z_0 = \\frac{120\\pi}{\\sqrt{4.4} \\cdot \\left(1.125 + 1.393 + 0.667 \\cdot \\ln(1.125 + 1.444)\\right)}$$<\/li>\n<li>$$= \\frac{376.99}{2.097 \\cdot \\left(2.518 + 0.667 \\cdot \\ln(2.569)\\right)}$$<\/li>\n<li>$$\u2248 \\frac{376.99}{2.097 \\cdot (2.518 + 0.667 \\cdot 0.943)}$$<\/li>\n<li>$$\u2248 \\frac{376.99}{2.097 \\cdot 3.146} \u2248 \\frac{376.99}{6.598} \u2248 57.13~\\Omega$$<\/li>\n<\/ol>\n<p>\n\r\n<\/section><br \/>\nMicrostrip transmission lines are widely used in high-frequency PCB design, especially in RF and microwave circuits. This calculator allows designers to compute the characteristic impedance to ensure proper signal integrity and impedance matching. It is critical in preventing signal reflections, minimizing crosstalk, and ensuring high-performance interconnects. Whether for antennas, filters, or digital buses, impedance-controlled traces are a must in modern board layouts.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>This calculator estimates the characteristic impedance of microstrip transmission lines based on trace width, substrate height, and dielectric constant. It\u2019s essential for designing high-speed PCBs and RF circuits where impedance matching is critical.<\/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-64446","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\/64446","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=64446"}],"version-history":[{"count":2,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/64446\/revisions"}],"predecessor-version":[{"id":64448,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/64446\/revisions\/64448"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=64446"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=64446"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=64446"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}