Smith Chart — Matching Concept

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 360 360" width="360" height="360">
  <style>
    text { font:11px Inter, sans-serif; fill:#0f172a; font-weight:600; text-anchor:middle; }
  </style>
  <!-- Unit circle -->
  <circle cx="180" cy="180" r="140" fill="white" stroke="#0f172a" stroke-width="1.6"/>
  <!-- Constant-resistance circles -->
  <circle cx="220" cy="180" r="100" fill="none" stroke="#94a3b8"/>
  <circle cx="250" cy="180" r="70"  fill="none" stroke="#94a3b8"/>
  <circle cx="275" cy="180" r="45"  fill="none" stroke="#94a3b8"/>
  <!-- Constant-reactance arcs -->
  <path d="M180,180 A100,100 0 0,1 320,180" fill="none" stroke="#cbd5e1"/>
  <path d="M180,180 A100,100 0 0,0 320,180" fill="none" stroke="#cbd5e1"/>
  <!-- Real axis -->
  <line x1="40"  y1="180" x2="320" y2="180" stroke="#0f172a"/>
  <text x="40"  y="174">Z=0</text>
  <text x="320" y="174">Z=∞</text>
  <text x="180" y="174">Z₀</text>
  <!-- Load mark + path -->
  <circle cx="245" cy="115" r="6" fill="#dc2626"/>
  <text x="270" y="105">Z_L</text>
  <path d="M245,115 A140,140 0 0,1 180,180" fill="none" stroke="#3666ff" stroke-width="2" stroke-dasharray="4 2"/>
  <circle cx="180" cy="180" r="6" fill="#16a34a"/>
  <text x="180" y="200">matched</text>
</svg>