RF Foundations Revisited with RFDH
A study path from wavelength and electrical length through 50 ohms, transmission lines, reflection, S-parameters, and decibels.
RF · Microwave
RFDH-based RF and Microwave Study Map
My recomputed and redrawn RF study map connecting public RFDH learning pages with my microwave coursework, Cadence screens, and FMCW work.
32 Notes · 17 Redraws
Read in order or choose a series
Every linked page includes equations, a recomputed example, two original diagrams, my coursework connection, and the public source pages I read.
RF calculatorsSeries
Five guided paths
Impedance, Reflection, and S-parameters
Reference planes connect load impedance, reflection, VSWR, the S-matrix, VNA practice, and cascade calculations.
Smith Chart and Matching
Ten steps from normalization and L/C movement to admittance, line rotation, and single-stub matching.
RF Linearity, Noise, and Power
P1dB, IMD, IP3, and cascaded noise figure are calculated in one signal chain without conflating the metrics.
RF Circuit Blocks and the FMCW Signal Chain
Amplifiers, oscillators, PLLs, mixers, filters, couplers, isolators, and antennas connected to an FMCW chain.
core
Core RF Path
Starting RF Study: Wavelength and Electrical Length
I started by asking why RF is more than a label for high frequency. When physical size is no longer negligible relative to wavelength, phase and reflection must be tracked along position.
Reading 50 Ohms, Ports, and Matching as One Flow
Memorizing 50 ohms, ports, and matching separately made S-parameter setups confusing. I drew the source-line-load reference planes first and connected all three terms on one path.
Comparing Transmission Lines, Microstrip, CPW, Coax, and Waveguide
Instead of listing line names, I compared each structure by return path, field confinement, mode, and fabrication variables.
Converting Reflection Coefficient, Return Loss, and VSWR
I rewrote the conversion order so that sign conventions and ratios are not mixed when one mismatch is expressed three ways.
Reading the S-Parameter Matrix and VNA Screens
I relabeled S11, S21, S31, and S23 by excitation and observation ports rather than treating them as curve names.
Checking dB and dBm Calculations by Hand
I write the reference and unit first to avoid mixing a dB ratio with absolute dBm power.
Separating Harmonics, IMD, P1dB, and IP3 on One Graph
I moved beyond small-signal gain and tracked how fundamentals and distortion change as input level rises.
Recording VNA Calibration and Reference Planes
Before placing simulation and instrument results in one table, I drew the calibration plane and fixture boundary.
Cascade Noise Figure and First-Stage Gain
I revisited Friis' equation to see why receiver noise figures cannot simply be added in dB.
Connecting I/Q, Modulation, Channel, and BER
I separated the digital-communications signal flow from the RF front end, then connected baseband I/Q through carrier, channel, and receiver decisions.
Re-reading My Microstrip, Matching, Wilkinson, and Branch-Line Work
I placed RFDH concepts beside my actual Cadence coursework screens and separated design equations, entered geometry, and stored markers.
From RF Circuits to FMCW Radar Signal Processing
I connected RF-circuit study to FMCW signal processing through chirp generation, transmit/receive chains, mixing, and IF sampling.
smith-chart
Smith Chart in 10 Parts
Why Use a Smith Chart
I used the RFDH Smith-chart notes to revisit mapping complex reflection and impedance on one bounded plane with a hand calculation and my own diagram.
Normalized Impedance
I used the RFDH Smith-chart notes to revisit normalizing by reference impedance and restoring ohms with a hand calculation and my own diagram.
Reading Resistance and Reactance Circles
I used the RFDH Smith-chart notes to revisit reading intersections of constant-resistance circles and reactance arcs with a hand calculation and my own diagram.
Load and Reflection Coefficient
I used the RFDH Smith-chart notes to revisit reading |Γ| and phase from distance and angle with a hand calculation and my own diagram.
Series L and C Movement
I used the RFDH Smith-chart notes to revisit how series reactance moves along a constant-resistance circle with a hand calculation and my own diagram.
Shunt L and C in Admittance
I used the RFDH Smith-chart notes to revisit adding parallel elements as susceptance on the admittance chart with a hand calculation and my own diagram.
Switching Between Impedance and Admittance
I used the RFDH Smith-chart notes to revisit using a 180-degree rotation to switch between z and y with a hand calculation and my own diagram.
Transmission-Line Rotation
I used the RFDH Smith-chart notes to revisit how line length rotates phase on a constant-|Γ| circle with a hand calculation and my own diagram.
Two Single-Stub Matching Solutions
I used the RFDH Smith-chart notes to revisit finding a g=1 point and cancelling susceptance with a stub with a hand calculation and my own diagram.
Re-reading Cadence L-Matching and Stub Screens
I used the RFDH Smith-chart notes to revisit re-reading my stored Smith trajectory by design frequency and component order with a hand calculation and my own diagram.
circuit-blocks
RF Circuit Blocks in 10 Parts
Amplifiers: Gain, Noise, and Linearity
Rather than memorize the whole transceiver, I isolated the inputs, outputs, and role of Amplifiers: Gain, Noise, and Linearity.
Oscillators and VCOs
Rather than memorize the whole transceiver, I isolated the inputs, outputs, and role of Oscillators and VCOs.
PLLs and Frequency Synthesis
Rather than memorize the whole transceiver, I isolated the inputs, outputs, and role of PLLs and Frequency Synthesis.
Mixers and IF Selection
Rather than memorize the whole transceiver, I isolated the inputs, outputs, and role of Mixers and IF Selection.
Frequency Multipliers
Rather than memorize the whole transceiver, I isolated the inputs, outputs, and role of Frequency Multipliers.
RF Filters and Prototype Responses
Rather than memorize the whole transceiver, I isolated the inputs, outputs, and role of RF Filters and Prototype Responses.
Diplexers and Duplexers
Rather than memorize the whole transceiver, I isolated the inputs, outputs, and role of Diplexers and Duplexers.
Couplers, Dividers, and Combiners
Rather than memorize the whole transceiver, I isolated the inputs, outputs, and role of Couplers, Dividers, and Combiners.
Isolators and Circulators
Rather than memorize the whole transceiver, I isolated the inputs, outputs, and role of Isolators and Circulators.
Reading an Antenna as an RF Port
Rather than memorize the whole transceiver, I isolated the inputs, outputs, and role of Reading an Antenna as an RF Port.