RF Design

RF design tools: free, online, instant

28 everyday RF design calculators from WENSHING — antennas and matching, couplers, filters, transmission-line impedance, noise and attenuation, and board measurement. Each comes with a diagram and input/output notes and runs in your browser.

Antennas & matching Couplers, dividers & baluns Filters Transmission-line impedance System calculations Material measurement

Antennas & matching

Antenna design referenceAntenna types, lengths and layout tips by band.Open tool ›Antenna impedance matchingEnter antenna impedance and frequency to get L/π matching networks with a Smith-chart path.Open tool ›Loop antenna (keyboard / mouse)PCB loop size, inductance and tuning capacitor for wireless keyboards, mice and remotes.Open tool ›

Couplers, dividers & baluns

Directional couplerCoupling and frequency → even/odd-mode impedances, line width and spacing.Open tool ›Wilkinson divider (unequal split)Split ratio → λ/4 line impedances and isolation resistor.Open tool ›Narrowband balunSingle-ended to differential: impedances and frequency → LC balun values.Open tool ›

Filters

Chebyshev low-pass filterCut-off, order and ripple → LC values.Open tool ›Butterworth (maximally flat) LPFFlattest passband: cut-off and order → component values.Open tool ›5-section distributed LPFStepped-impedance microstrip LPF: widths and lengths per section.Open tool ›Chebyshev high-pass filterCut-off, order and ripple → high-pass LC values.Open tool ›Maximally flat high-pass filterButterworth-response high-pass LC values.Open tool ›Chebyshev band-pass filterCentre frequency, bandwidth, order, ripple → band-pass LC values.Open tool ›Maximally flat band-pass filterButterworth-response band-pass LC values.Open tool ›Chebyshev band-stop filterReject an interfering band: notch LC values.Open tool ›Maximally flat band-stop filterButterworth-response band-stop LC values.Open tool ›

Transmission-line impedance

Microstrip lineBoard height, εr and width ↔ characteristic impedance (e.g. 50 Ω width).Open tool ›Suspended microstrip lineMicrostrip impedance with an air gap under the substrate.Open tool ›Inverted microstrip lineInverted microstrip (conductor facing down over air) impedance.Open tool ›Grounded coplanar waveguideThe most common RF trace: width, gap and bottom ground → impedance.Open tool ›Coplanar waveguideCoplanar waveguide without bottom ground.Open tool ›Coplanar stripsDifferential impedance of two parallel strips.Open tool ›StriplineImpedance of an inner-layer trace between two grounds.Open tool ›Slot lineImpedance of a slot in a ground plane.Open tool ›Coaxial lineInner/outer diameter and εr → coaxial impedance.Open tool ›

System calculations

LoRa range and airtimePayload, data and distance → best SF, bandwidth, TX power and time on air.Open tool ›Cascaded noise figurePer-stage gain and NF → total receiver-chain noise figure.Open tool ›π / T resistive attenuatorAttenuation and impedance → π or T resistor values.Open tool ›HFSS waveport sizeEstimate HFSS wave-port width and height before simulation.Open tool ›

Material measurement

PCB dielectric constant measurementDerive board εr from a measured resonance for impedance and antenna design.Open tool ›

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