---
title: "Designs an L-network impedance matching circuit between two real impedances at a given frequency. Computes the required shunt and series reactive components (inductor and capacitor) to transform the source impedance to the load impedance. The network Q factor is sqrt(Rh/Rl - 1) where Rh is the higher impedance. Topology is automatically selected: the shunt element is placed across the higher impedance side. Essential for antenna matching, amplifier input/output matching, and maximizing power transfer. Chain from lc_resonance to match at a tank circuit's resonant frequency."
method: POST
path: "/api/impedance_match"
tags: ["pcb"]
---

# Designs an L-network impedance matching circuit between two real impedances at a given frequency. Computes the required shunt and series reactive components (inductor and capacitor) to transform the source impedance to the load impedance. The network Q factor is sqrt(Rh/Rl - 1) where Rh is the higher impedance. Topology is automatically selected: the shunt element is placed across the higher impedance side. Essential for antenna matching, amplifier input/output matching, and maximizing power transfer. Chain from lc_resonance to match at a tank circuit's resonant frequency.

`POST /api/impedance_match`

## Request

- Base URL: `https://calc.engineer`
- URL: `https://calc.engineer/api/impedance_match`
- Auth: none declared

## Request body

- object
  - `source_ohm` number, required: Source impedance in ohms (real, resistive). Must differ from load impedance.
  - `load_ohm` number, required: Load impedance in ohms (real, resistive). Must differ from source impedance.
  - `freq_mhz` number, required: Design frequency in megahertz for component value calculation.

## Response `200`

Computed result for impedance_match

- object
  - `result` object, required
    - `q_factor` number, required: Network Q factor = sqrt(Rh/Rl - 1), where Rh is the higher impedance.
    - `topology` string, required: Description of the L-network arrangement (which side gets shunt vs series element).
    - `shunt_component` object, required
      - `type` 'inductor' | 'capacitor', required: Component type: inductor or capacitor.
      - `value_h` number: Inductance value in henries, present when type is inductor.
      - `value_f` number: Capacitance value in farads, present when type is capacitor.
      - `reactance_ohm` number, required: Reactance magnitude in ohms at the design frequency.
    - `series_component` object, required
      - `type` 'inductor' | 'capacitor', required: Component type: inductor or capacitor.
      - `value_h` number: Inductance value in henries, present when type is inductor.
      - `value_f` number: Capacitance value in farads, present when type is capacitor.
      - `reactance_ohm` number, required: Reactance magnitude in ohms at the design frequency.
  - `tool` string, required
  - `version` string, required
  - `computed_at` string, date-time, required
  - `chain` object, required
    - `feeds` unknown[]
      - unknown
    - `accepts_from` unknown[]
      - unknown

## Other responses

- `400`: Validation error or invalid JSON
- `404`: Tool not found

---

[API](https://skmtc.dev/calc/apis/calc-engineer-api.md) · [All operations](https://skmtc.dev/calc/apis/calc-engineer-api/llms.txt) · [OpenAPI document](https://skmtc.dev/calc/apis/calc-engineer-api/revisions/8830480ec488?raw)