RF & Microwave Calculators: Impedance Matching and Transmission Lines

This collection of RF and microwave calculators covers the transmission line and impedance matching tasks that come up in high-frequency circuit design. Whether you are routing a PCB trace, building an antenna, or tuning an amplifier, these tools help you get the numbers right without digging through formulas.Compute trace impedance with the Microstrip Impedance, Stripline Impedance, and Microstrip Differential Impedance calculatorsDesign matching circuits using the L Matching Network, PI Network, and T Matching Network toolsEstimate coupling with PCB Microstrip Crosstalk and field exposure with RF Power DensityBuild coils with the Helical Antenna calculatorThese calculators are aimed at RF engineers, PCB layout designers, ham radio enthusiasts, and students working with high-frequency electronics.

Helical Antenna

Calculate the dimensions of an axial-mode helical antenna from its operating frequency and number of turns. Get the wavelength, helix diameter, turn spacing (pitch), and total antenna length in seconds.

Parallel Wire Impedance

Calculate the characteristic impedance of a parallel wire (two-wire) transmission line from the wire diameter and center-to-center spacing. Useful for designing twin-lead, ladder line, and balanced RF feeder systems.

PI Network Impedance Matching

Calculate the component values for a PI matching network that transforms a lower source resistance to a higher load resistance. Enter Rs, Rl and the operating frequency to get Q, the reactances, capacitance and inductance.

Microstrip Transmission Lines Impedance

Estimate the characteristic impedance of a microstrip transmission line from the dielectric constant, substrate height, trace width and copper thickness. Enter your PCB stack-up values to get Z0 in ohms for RF and high-speed design.

Stripline Impedance

Calculate the characteristic impedance of a symmetric stripline trace on a PCB. Enter the dielectric constant, trace width, copper thickness, and dielectric height to get Z0 in ohms.

Microstrip Impedance From Zo

Find the microstrip trace width needed to hit a target characteristic impedance (Zo). Enter the target impedance, dielectric constant and substrate height, and get the required width in mm.

Microstrip Impedance

Calculate the characteristic impedance of a microstrip transmission line from the dielectric constant, substrate height, trace width and trace thickness. Essential for impedance-controlled PCB routing in RF and high-speed digital design.

L Matching Network

Calculate the component values for an L-network that matches a low source resistance to a higher load resistance at a given RF frequency. Enter the two resistances and the operating frequency to get Q, the series inductance, and the parallel capacitance.

RF Power Density

Calculate RF power density in W/m² from transmitter power, antenna gain (dBi) and distance. Enter three values to estimate far-field radiation intensity for exposure and compliance checks.

T Matching Network

Computes the capacitor and inductor values for a T impedance matching network from frequency, source and load impedance, and Q factor — for RF, antenna and amplifier matching.

Microstrip Differential Impedance

Estimate the differential impedance of an edge-coupled microstrip pair on a PCB by entering the single-ended impedance, trace spacing, and substrate height — essential for USB, HDMI, LVDS, and PCIe routing.

Stripline PCB Differential Impedance

Estimate the differential impedance of a stripline pair on a multilayer PCB. Enter the single-ended impedance, trace spacing, and height to the reference plane to get Z_diff in ohms.

Skin Depth

Calculate the skin depth of an alternating current in a conductor from frequency, resistivity and relative permeability. Enter the material properties to see how deep AC current actually penetrates.

Microstrip PCB Impedance

Calculate the characteristic impedance of a microstrip PCB trace from the substrate's dielectric constant, trace width, substrate height, and copper thickness. Essential for controlled-impedance routing in high-speed and RF designs.

PCB Microstrip Crosstalk

Estimate the near-end crosstalk (NEXT) between two parallel microstrip traces on a PCB. Enter the trace spacing and substrate height to get the coupling level in dB.