Know what the numbers mean before you design
Tutorials and tools for RF engineers, with a plain-language layer for students.
Tutorials
Expert detail first, then a plain-language version.
Low-Pass to High-Pass Transformation: Swapping L and CThe mapping ω → −ωc/ω turns a series-inductor element g into a series capacitor C' = 1/(Z0·ωc·g) and a shunt-capacitor element g into a shunt inductor L' = Z0/(ωc·g). For g = 1, 50 Ω and 1 GHz that gives 3.18 pF and 7.96 nH.Unilateral Figure of Merit: When Can You Ignore S12?The true gain lies between 1/(1+U)² and 1/(1−U)² times the unilateral gain G_TU. For U = 0.1 that is −0.83 dB to +0.92 dB, and for U = 0.05 it is about −0.42 dB to +0.45 dB.Hartley vs Weaver Image-Reject Receivers ComparedBoth receivers cancel the image by combining quadrature I and Q paths, but the rejection is always finite. For small errors IRR ≈ 4/(ε² + θ²), so a 1% gain error with a 0.01 rad phase error gives about 43 dB.How Much Duplexer Isolation? TX Noise in the RX BandRequired isolation equals the TX noise in the RX band minus the receiver noise floor, plus a margin. With -60 dBm of TX noise in 10 MHz, a -99 dBm floor and a 10 dB margin, the duplexer needs 49 dB of TX-to-RX isolation.How to Pick Filter Order From a Rejection RequirementA Butterworth needs N ≥ log10(10^(LAs/10) − 1) / (2·log10(ωs/ωc)), so 40 dB at twice the cut-off needs N = 7. A Chebyshev with 0.5 dB ripple meets the same 40 dB at ratio 2 with N = 5.All tutorialsTools
Formulas and limits shown.
Attenuator padsdBm converterL-network matchingMicrostrip impedanceS2P viewerVSWR and return lossAll calculatorsWhat this site covers
RF View is written for engineers who read S-parameters for a living and for students who are meeting them for the first time. The library is organised by the questions that come up on a mobile handset front end: concepts such as transmission lines, the Smith chart, noise figure and amplifier stability; step-by-step tutorials for filter design, calibration and matching; and component pages for duplexers, connectors and other parts read through their S-parameters.
Each article gives the expert explanation first, with the formulas and one worked example computed in full, then the same idea in plain language with the usual beginner mistakes. Numbers in the examples are recomputed before publishing, and every tutorial lists its references. If you find a mistake, tell us and the article is corrected and its date updated.