RF & Microwave Engineering Calculators
119 free calculators and simulators covering impedance matching, transmission lines, filters, antennas, amplifiers, waveguides, and MRI coils — plus 68 wiki articles. No install. Runs in your browser.
117🧮 Calculators
2🔬 Simulators
64📖 Wiki Articles
7🎮 Games
Fundamentals & EM10 tools
Wavelength
Free-space λ from frequency and dielectric constant.
Freq / λ / Energy
Live converter: frequency, wavelength, period, photon energy, B₀.
Skin Depth
Conductor skin depth vs frequency and conductivity.
dBm ↔ Watts
Convert between dBm and watts in either direction.
Plane Wave / Power Density
Wave impedance, E/H fields and power density (Poynting) for a plane wave.
Field Strength Converter
V/m ↔ dBµV/m ↔ A/m ↔ W/m², or field from EIRP and distance.
Dielectric Boundary (Fresnel)
Reflection/transmission vs angle, Brewster and critical angles at an interface.
Dielectric Loss Tangent
Complex permittivity, dielectric Q, attenuation and wavelength in a material.
Thermal (kTB) Noise
Johnson–Nyquist noise voltage/current and available noise power kTB.
Shielding Effectiveness
Absorption + reflection loss and total SE of a metal barrier (far-field plane wave).
Resonance & Passives13 tools
LC Circuit Solver
Solve for L, C, or f₀ — fill any two, get the third.
LC Tuning Capacitor
Capacitance needed to resonate a given inductor at a target frequency.
Coupled Resonators
Mode splitting, bandwidth, and coupling regime for two magnetically coupled LC tanks.
Bandpass Calculator
f₀, Q, and bandwidth from R, L, C for series or parallel RLC.
Solenoid Inductance
Inductance of a single-layer air-core or cored coil (Wheeler's formula) from turns, diameter, and length.
Varactor C–V Tuning
Varactor capacitance vs bias, tuning ratio, and resonant-frequency tuning range.
Parallel-Plate Capacitor
Capacitance from plate area, gap, dielectric and plate count, plus field and stored energy.
Bond Wire Inductance
Parasitic inductance and reactance of a bond wire (Grover formula).
Wire Inductance
Self-inductance of a straight wire, circular loop, or two-wire line.
Toroid Inductor
Turns from the core AL value and target inductance (L = AL·N²), plus a flux-density check.
Capacitor SRF
Self-resonant frequency from C and parasitic ESL, plus Q and reactance at frequency.
Resonator Q
Loaded/unloaded/external Q, 3-dB bandwidth, coupling and insertion loss.
Ferrite Bead / Choke
Approximate bead impedance from a series R–L model or a datasheet point.
Transmission Lines11 tools
Microstrip
Z₀ and εeff from geometry, or trace width from target Z₀.
Coaxial Line
Z₀, velocity factor, and cutoff frequency for coax cable.
Stripline
Fully shielded TEM stripline between two ground planes.
Coplanar Waveguide
CPW and GCPW Z₀ using elliptic integral conformal mapping.
Differential Pair
Z_diff and Z_odd for edge-coupled microstrip pairs.
Stub Calculator
Open/short stub length for a target shunt susceptance.
Quarter-Wave Transformer
λ/4 impedance transformer Z and physical length.
TL Loss & Delay
Conductor + dielectric insertion loss and propagation delay for microstrip and coax.
TDR Fault Distance
Locate a cable fault from the echo delay and velocity factor, plus the fault impedance.
PCB Via Parasitics
Via inductance, antipad capacitance, and self-resonant frequency.
Coax Power Handling
Peak voltage-breakdown power and Z₀ of a coaxial line from geometry and dielectric.
Matching & Dividers17 tools
Interactive Smith Chart
HiDPI Smith Chart — click to read, pin points, rotate with stubs.
VSWR / Return Loss
Live converter between VSWR, |Γ|, return loss, and mismatch loss.
L-Network Matcher
L, C values for single-frequency impedance matching.
Pi / T Network
Pi and T matching networks with free choice of loaded Q.
Impedance Matching Network
L-network for complex ZS→ZL with Smith Chart trajectories.
Capacitor Network
Total capacitance for series and parallel combinations.
LC BALUN
Lattice and Pi BALUN design with impedance transformation.
Wilkinson Divider
Equal and unequal power splits with isolation resistor.
Coupler & Hybrid
Coupled-line, branchline (90°), and rat-race (180°) hybrid design.
Power Combining
N-way combiner output power with efficiency and failure analysis.
Digital Phase Shifter
LSB step, number of states, and RMS quantization error of an N-bit phase shifter.
Mismatch Loss
Mismatch loss, return loss, VSWR, |Γ| and reflected/transmitted power.
Single-Stub Matching
Shunt-stub position and open/short length to match a complex load (both solutions).
Double-Stub Tuner
Two-stub matching for a fixed spacing, both solutions, with the forbidden-region check.
Multisection λ/4 Transformer
Binomial or Chebyshev multisection transformer: section impedances and bandwidth.
Tapered-Line Matching
Exponential, triangular and Klopfenstein taper reflection response and cutoff.
Bode–Fano Limit
Theoretical best matching bandwidth (or minimum reflection) for a reactive load.
Filters & Attenuators5 tools
First-Order Filter
RC & RL low-pass / high-pass: cutoff frequency, τ, and roll-off.
LC Filter Designer
Butterworth/Chebyshev LP/HP up to 9th order with BOM.
Attenuator Designer
Pi, T, L-pad, and Bridged-T resistor values for any attenuation.
Stepped-Z LPF
Microstrip stepped-impedance LPF: Butterworth or Chebyshev, with trace dimensions.
Filter Group Delay
Band-center group delay of a Butterworth or Chebyshev lowpass prototype from its poles.
Amplifiers & Devices17 tools
Cascaded Noise Figure
System NF and gain for up to 8 cascaded stages (Friis).
Amplifier Stability
Rollett K-factor, µ-factor, MAG/MSG from S-parameters. Unconditional stability check.
IP3 & Intermodulation
OIP3, IM3 product power, and IMD ratio from IIP3 and gain.
Transistor fT / fmax
Transition and maximum oscillation frequency from gm, capacitances and gate resistance.
Unilateral Transducer Gain
Maximum gain from S-parameter magnitudes, with source and load match contributions.
LNA Noise Match
Noise figure for any source reflection from the noise parameters Fmin, Rn and Γopt.
Noise Figure (Y-Factor)
Noise figure and noise temperature from the Y-factor measurement and source ENR.
PLL Loop Filter
Type-2 3rd-order passive loop filter component values from bandwidth and phase margin.
Phase Noise → Jitter
Integrate a piecewise phase noise profile to RMS jitter.
DDS Frequency
Output frequency, tuning word and resolution of a direct digital synthesizer.
Noise Temp ↔ NF
Convert noise figure (dB) ↔ noise factor ↔ equivalent noise temperature (K), plus added noise power.
Leeson Phase Noise
Predict oscillator L(fm) from loaded Q, noise figure, power and flicker corner.
PA Load-Line (Cripps)
Optimum load, maximum output power and drain efficiency for an RF power amplifier.
Junction Temperature
Device junction temperature and margin from the θjc/θcs/θsa thermal chain.
Quartz Crystal Resonator
Series/parallel resonance, Q, capacitance ratio and pullability from motional L1/C1/R1/C0.
Amplifier Design Circles
Stability, available-gain and noise-figure circles on the source-plane Smith chart from S-parameters.
Simultaneous Conjugate Match
Source/load reflections and maximum transducer gain for a bilateral amplifier.
Receivers & DSP11 tools
Receiver Sensitivity / MDS
Noise floor, minimum detectable signal, and spurious-free dynamic range from bandwidth, NF, SNR and IIP3.
Image Frequency & Rejection
Image and LO frequencies plus image-rejection ratio from I/Q gain and phase imbalance.
ADC SNR / ENOB
Quantization SNR, aperture-jitter-limited SNR, combined SNR and effective number of bits.
EVM ↔ SNR Converter
Convert error vector magnitude to/from SNR/MER, with the densest supportable QAM order.
Bandpass Sampling
Nyquist zone, aliased IF, spectral inversion and minimum sample rate for undersampling.
Spectrum Analyzer DANL
Displayed average noise level and sensitivity from RBW, noise figure and attenuation.
RF Cascade Analyzer
Cumulative gain, cascaded noise figure, IIP3/IIP2, noise floor and SFDR for a multi-stage chain.
Mixer Spur Chart
m·LO ± n·RF spurious products landing in the IF band, plus image and half-IF frequencies.
Modulation Bandwidth & Eb/N0
Symbol rate, raised-cosine occupied bandwidth, spectral efficiency and Eb/N0 ↔ SNR.
BER vs Eb/N0
Bit error rate for BPSK/QPSK/M-PSK/M-QAM in AWGN, with the waterfall curve and required Eb/N0.
OFDM Parameters
Symbol time, cyclic-prefix overhead, occupied bandwidth, PAPR bound and data rate.
Antennas & Arrays10 tools
Dipole Antenna
Half-wave dipole arm length and shortening factor.
Patch Antenna
Patch width, length, and effective permittivity for any substrate.
Array Factor Plotter
Polar radiation pattern for N-element linear arrays with steering.
Helical Antenna
Axial-mode helix gain, HPBW, and dimensions via Kraus formulas.
Yagi-Uda Antenna
Gain, element lengths, and boom size for 2–9 element Yagis (NBS/Viezbicke tables).
Aperture Antenna Gain
Dish/horn gain from area and efficiency, plus the far-field (Fraunhofer) distance.
Parabolic Dish
Reflector gain, half-power/first-null beamwidth and effective aperture from diameter.
Horn Antenna
Pyramidal/conical horn gain, effective aperture and beamwidth from the aperture size.
Antenna Gain Converter
dBi ↔ dBd, EIRP, effective aperture (Gλ²/4π) and the far-field distance.
Monopole & Small Loop
λ/4 monopole length/Rr/gain and small-loop radiation resistance and gain.
Propagation, Radar & Links12 tools
Friis Equation
Received power from EIRP, path loss, and antenna gains.
Link Budget
End-to-end RF link: EIRP, path loss, noise floor, SNR margin.
Fresnel Zone & Clearance
First-zone radius and the 60% clearance needed for a line-of-sight link.
Path Loss Models
Free-space, two-ray, Okumura-Hata and COST-231 propagation loss.
Radar Range Equation
R_max and received power from transmit power, RCS, and gains.
Shannon Capacity & BER
Channel capacity, spectral efficiency, Eb/N0↔SNR and BPSK/QPSK bit error rate.
Processing Gain & Jamming Margin
Spread-spectrum processing gain from chip/data rate, plus jamming margin.
Doppler Shift
Doppler frequency shift for one-way links and two-way radar from speed and angle.
G/T Figure of Merit
Receive-system G/T and system noise temperature from gain, Tant and receiver NF.
FMCW Radar
Range/velocity resolution, beat frequency and chirp slope for a frequency-modulated CW radar.
Radar PRF & Ambiguity
Unambiguous range and velocity, blind speeds, PRI and duty cycle from the PRF.
Radar Cross Section
RCS of a sphere, flat plate, cylinder or trihedral corner in m² and dBsm.
Waveguide2 tools
Rectangular Waveguide
TE/TM mode cutoffs, guide wavelength, wave impedance, and conductor loss.
Circular Waveguide
TE/TM mode cutoffs using Bessel zeros, guide wavelength, wave impedance, and conductor loss.
MRI Coils & Tools6 tools
Loop Inductance
Inductance of a single circular loop (Rosa formula).
Simple RF Coil Designer
Single-turn loop inductance L and the tuning capacitor C for resonance at f.
Advanced RF Coil Designer
Complete MRI surface receive coil design with matching network.
Birdcage Coil
LP/HP birdcage MRI volume coil: element values and mode frequencies.
SAR Estimator
Local SAR from B₁⁺, frequency, tissue type vs IEC limits.
Array Decoupling
Mutual inductance and overlap/capacitive/preamp decoupling.
Converters3 tools
S/Z/Y/ABCD Converter
Convert between all four 2-port parameter representations.
S-Parameter Plotter
Plot Touchstone .s1p–.s4p files with Chart.js.
E-Series Finder
Nearest standard R, C, or L value in E6–E192 with % error.
Simulators2 tools
RF Circuit Simulator
ABCD-matrix ladder network simulator: S-params, VSWR, group delay.
SPICE Simulator
MNA-based SPICE engine: .AC, .DC, .OP, .TRAN analyses in browser.
📖 Wiki — 68 Reference Articles
dB & dBm
Complex Impedance
Smith Chart Tutorial
VSWR & Return Loss
VNA Measurements
S-Parameters
Impedance Matching
Transmission Lines
Microwave Lines
PCB RF Design
Coax Cable Reference
RF Connectors
Attenuators
RF Filters
Group Delay
Power Dividers
IP3 & IMD
RF Amplifiers
PA Design
Noise in RF
Cascade Analysis
Link Budgets
Superheterodyne Rx
Mixers
Modulation
Oscillators
Crystal Resonators
Thermal Management
PLL & Synthesis
Phase Noise
Radar
FMCW Radar
Antennas
Aperture Antennas
Polarisation
Frequency Bands
EMC Shielding
RF Safety
EM Waves
Maxwell's Equations
Skin Effect
Dielectrics
Magnetic Materials
Waveguides
Microwave Components
BALUNs
NMR Basics
Coil Design
Coil Types
Coil SNR
Birdcage Coil
Phased Arrays
Preamp Decoupling
MRI SAR
Gradient Coils
B₁ Mapping
MRI Hardware
MRI Sequences
MRI Contrast
MRI Artefacts
Parallel Imaging
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