RF Design Wiki

From RF Design Wiki · By the RF Design Wiki editorial team · Published October 21, 2026 · Last reviewed October 21, 2026 · How we research

RF Design Wiki is a sourced, vendor-neutral educational reference on radio-frequency and microwave design. It explains the fundamentals (decibels, noise, wavelength), transmission lines, impedance matching and the Smith chart, S-parameters, filters, amplifiers, mixers, oscillators and PLLs, antennas and propagation, PCB layout, EMC, test and measurement, simulation and standards, with formulas and citations to textbooks, IEEE papers, ITU and FCC texts and manufacturer application notes.

Where should you start?

What is RF design?: RF design is the engineering of circuits and systems that generate, transmit, receive and process radio-frequency signals, roughly 3 kHz to 300 GHz.
What are decibels, dBm and dBi?: How decibels work in RF engineering: power and voltage ratios, dBm, dBW, dBc, dBi and dBµV, with conversions and worked values.
What is a transmission line?: Transmission line theory for RF: the distributed RLGC model, telegrapher's equations, characteristic impedance, propagation constant, loss and standing waves.
How do you read and use a Smith chart?: How the Smith chart maps normalized impedance onto the reflection-coefficient plane, how to read circles and arcs, and how to design matching networks with it.
What are S-parameters?: Scattering parameters describe RF networks by incident and reflected waves. Definitions of S11, S21, S12, S22, properties, conversion to dB, and why VNAs measure them.
What is noise figure?: Noise figure measures how much a device degrades signal-to-noise ratio. Definitions, Friis cascade formula, noise temperature conversions and design implications.
How does an RF power amplifier work?: RF power amplifier fundamentals: load-line design, optimum load resistance, output matching, efficiency, linearity, thermal limits and ruggedness.
What is phase noise and how is it specified?: Phase noise describes short-term frequency instability as single-sideband noise relative to the carrier, in dBc/Hz at an offset. Leeson's equation, effects on receivers and transmitters.
What are the fundamental antenna parameters?: Core antenna parameters: radiation pattern, directivity, gain, efficiency, input impedance, bandwidth, polarization, effective aperture, and near- and far-field regions.
How do you calculate an RF link budget?: A link budget sums transmit power, antenna gains, losses and path loss, and compares received power with receiver sensitivity to find link margin. Method and worked example.
What are the rules for good RF PCB layout?: Practical RF PCB layout rules: solid ground planes, controlled-impedance routing, via stitching, component placement, isolation between blocks, and transitions.
How does a vector network analyzer work?: How a VNA measures S-parameters: source, directional couplers, reference and test receivers, IF bandwidth, dynamic range, and common measurements from S11 to group delay.

What are the essential numbers of RF design?

Thermal noise is −174 dBm/Hz at 290 K.^[1]
Free-space wavelength is about 300/f(MHz) meters; 2.4 GHz is about 12.5 cm.
A 2:1 VSWR reflects 11% of power and costs 0.51 dB.
A half-wave dipole has about 2.15 dBi gain and ~73 Ω resistance.^[2]
Free-space path loss is 32.45 + 20·log10(f_MHz) + 20·log10(d_km) dB.^[3]

How is the wiki organized?

Articles are grouped into fundamentals, transmission lines, matching and S-parameters, filters and passives, amplifiers, mixers and frequency generation, antennas and propagation, receivers and systems, PCB layout and materials, EMC and EMI, test and measurement, simulation, and standards and bands. See the contents, the learning path, the glossary and the FAQ.

Frequently asked questions

What is this wiki?

An independent, sourced educational reference on RF design, written by the RF Design Wiki editorial team.

Who is it for?

Students, engineers moving into RF from other fields, and practitioners who want a quick, sourced refresher.

How are facts checked?

Formulas and facts are checked against textbooks, IEEE papers, ITU and FCC texts and manufacturer application notes.

References

Online sources accessed October 21, 2026; printed works cited by edition. See all sources.

“Microwave Engineering, 4th ed.”. D. M. Pozar, Wiley. 2012.
“Antenna Theory: Analysis and Design, 4th ed.”. C. A. Balanis, Wiley. 2016.
“Recommendation ITU-R P.525: Calculation of free-space attenuation”. ITU-R. current version.

Categories: Start here

Articles on RF Design Wiki

Start here	Main page What is RF design Learning path Design workflow
Fundamentals	Decibels and dBm RF power Wavelength and frequency Thermal noise Noise figure Noise temperature SNR and Eb/N0 Skin effect Q factor Nonlinearity and harmonics Intermodulation and IP3 P1dB compression Dynamic range and SFDR
Transmission lines	Transmission line theory Characteristic impedance Γ, VSWR and return loss Input impedance of a line Quarter-wave transformer Microstrip Stripline Coplanar waveguide Coaxial cable Waveguides RF connectors
Matching and S-parameters	Impedance matching Maximum power transfer Smith chart L-network matching Pi and T networks Stub matching Bode–Fano limit S-parameters Touchstone files Z, Y, ABCD parameters De-embedding Mixed-mode S-parameters
Filters and passives	RF filter basics Filter approximations LC filter design Microstrip filters Cavity and dielectric filters SAW and BAW filters Diplexers and duplexers Wilkinson divider Couplers and hybrids Baluns Circulators and isolators RF attenuators Passive components
Amplifiers	Gain definitions Amplifier stability LNA design Power amplifier basics PA classes Efficiency and PAE Doherty amplifier Linearization and DPD Load-pull Transistor technologies Transistor biasing ACPR and EVM
Mixers and frequency generation	RF mixers Mixer specifications Image frequency I/Q modulators Oscillator basics Crystal oscillators VCO design Phase noise Jitter from phase noise PLL basics PLL loop filter Fractional-N synthesis Direct digital synthesis Multipliers and dividers
Antennas and propagation	Antenna fundamentals Gain and directivity Dipole antenna Monopole antenna Patch antenna Arrays and beamforming Small antenna limits Polarization Friis equation Free-space path loss Link budget Multipath and fading Atmospheric and rain loss Path loss models Fresnel zones
Receivers and systems	Receiver architectures Superheterodyne Direct conversion Low-IF receiver Software-defined radio Receiver sensitivity Blocking and selectivity Transmitter architectures Modulation ADCs for RF Radar basics
PCB layout and materials	RF PCB layout RF PCB materials Grounding and vias Controlled-impedance stackup Decoupling RF shielding Thermal design
EMC and EMI	EMC and EMI basics FCC Part 15 CISPR standards Immunity and ESD EMI filters and ferrites Precompliance testing RF exposure limits
Test and measurement	Vector network analyzer VNA calibration Spectrum analyzer Noise figure measurement Phase noise measurement RF power measurement Signal generators TDR Antenna measurement Oscilloscopes for RF
Simulation	Simulation overview Harmonic balance EM simulation EM solver methods SPICE for RF
Standards and bands	Frequency bands Radar band letters ISM bands 5G NR bands Wi-Fi and Bluetooth RF GNSS frequencies Amateur radio bands Spectrum regulation
Reference	Formula cheat sheet Textbooks and references Glossary FAQ All sources
About	About Editorial policy