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64 illustrated reference articles on RF engineering, microwave design, and MRI physics — each with equations, diagrams, and links to the related calculators.

7⚡ Electromagnetics
27📻 RF Engineering
16🔌 Microwave
14🧲 MRI Physics
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⚡ Electromagnetics 7 articles
Maxwell's Equations
The four laws governing all classical electromagnetism.
Electromagnetic Waves
TEM waves, polarisation, Poynting vector, and the EM spectrum.
Transmission Line Theory
Telegrapher's equations, reflections, and standing waves.
Skin Effect
Current concentration at surfaces and its impact on RF resistance.
Transmission Line Loss
Conductor and dielectric loss in microstrip and coax; propagation delay.
Dielectrics and Permittivity
Dielectric constant, loss tangent, and substrate materials.
Magnetic Materials
Permeability, ferrites, and magnetic cores in RF.
📻 RF Engineering 27 articles
dB, dBm & Power Units
Decibel scale, dBm reference, dBc/dBi/dBW, and cascade arithmetic.
Complex Impedance & Reactance
Reactance, phasors, admittance, Q factor, and series/parallel equivalents.
VSWR & Return Loss
VSWR, |Γ|, return loss, and mismatch loss.
VNA Measurements
SOL calibration, port extension, time-domain gating, and tips.
Smith Chart Tutorial
How to read and use the Smith Chart for impedance matching design.
S-Parameters
Scattering parameters, return loss, and two-port network analysis.
Impedance Matching
Why matching matters and the main techniques.
RF Attenuators
Pi, T, L-pad, and Bridged-T attenuator design equations.
RF Filters
Butterworth, Chebyshev, and LC ladder filter design.
Stepped-Impedance LPF
Distributed low-pass filter using alternating high-Z and low-Z microstrip sections.
Coupled Resonators
Mode splitting, BW = k·f₀, and critical coupling for LC tank pairs.
E-Series Component Values
Standard resistor and capacitor values: E6 through E192.
Noise in RF Systems
Thermal noise, noise figure, and the Friis formula.
RF Amplifiers
LNAs, PAs, gain, stability, and linearity (P1dB, IP3).
Amplifier Stability (K & µ)
Rollett K-factor, µ-factor, MAG/MSG from S-parameters.
Power Amplifier Design
PA classes A–F, efficiency, back-off, Doherty, and DPD.
Intermodulation & IP3
IM3 products, IIP3/OIP3, IMD ratio, and cascaded IP3.
Power Dividers & Combiners
Wilkinson divider, hybrid couplers, and N-way combining.
Mixers and Frequency Conversion
Upconversion, downconversion, IQ mixers, and spurs.
Modulation Schemes
AM, FM, PSK, QAM, and OFDM basics.
Oscillators
Phase noise, VCOs, and oscillator design.
PLL & Frequency Synthesis
PFD, loop filter, VCO, integer-N vs fractional-N, reference spurs.
Phase Noise & Jitter
L(f) definition, Leeson model, 1/f² region, jitter integration.
Link Budgets
Systematic end-to-end RF link analysis.
Receiver Cascade Analysis
Combined NF, gain, and IP3 cascade with worked example.
Superheterodyne Receiver
Signal flow, image rejection, IF selection, and dynamic range.
Radar Fundamentals
Radar equation, range resolution, and Doppler effect.
🔌 Microwave Engineering 16 articles
Microwave Transmission Lines
Microstrip, CPW, stripline, and coax at microwave frequencies.
RF PCB Design
CPW, differential pairs, stripline, via parasitics, bond wire inductance.
Coaxial Cable Reference
RG-58, LMR-400, semi-rigid — attenuation, velocity factor, power ratings.
RF Connectors Reference
SMA, N-type, BNC, 2.92 mm, 1.85 mm — frequency limits and torque specs.
Antenna Fundamentals
Gain, directivity, polarisation, and radiation patterns.
Helical Antenna
Axial-mode helix: Kraus gain, HPBW, circular polarisation, and design.
Yagi-Uda Antenna
Element roles, gain tables, feed impedance, and matching.
Antenna Polarisation
Linear, CP, axial ratio, mismatch loss, and reading radiation patterns.
RF Frequency Bands
ITU and IEEE band designations, key allocations, antenna size reference.
Waveguides
Rectangular waveguide modes, cutoff frequency, and applications.
BALUNs and Hybrids
Balanced–unbalanced transitions and 90°/180° hybrids.
Microwave Passive Components
Couplers, circulators, attenuators, and power dividers.
FMCW & Pulsed Radar
Range resolution, Doppler, beat frequency, and range-Doppler matrix.
EMC Shielding
SE mechanisms, aperture leakage, cable shield transfer impedance.
RF Safety & Exposure
ICNIRP/FCC power density limits, SAR, and safe distance formula.
Phased Arrays
Electronic beam steering, array factor, and beamforming.
🧲 MRI Physics 14 articles
NMR Basics
Nuclear spin, Larmor precession, and the Bloch equations.
MRI Hardware
Main magnet, gradient coils, and RF system overview.
MRI Pulse Sequences
Spin echo, gradient echo, EPI, and k-space.
MRI Contrast & Relaxation
T1, T2, T2*, proton density, and contrast agents.
MRI Artefacts
Gibbs ringing, chemical shift, motion, and susceptibility artefacts.
Parallel Imaging
SENSE, GRAPPA, and accelerated acquisition.
MRI Gradient Coils
Gradient efficiency, slew rate, eddy currents, and PNS limits.
RF Coil Design
Tuning, matching, decoupling, and coil Q.
Coil Types
Volume coils, surface coils, phased arrays, and birdcages.
SNR in MRI Coils
Noise sources, filling factor, and optimising receive SNR.
Birdcage Coil
Theory, design equations, mode frequencies, and quadrature excitation.
Preamplifier Decoupling
Low-impedance preamp technique for array element isolation.
SAR and RF Safety
Specific absorption rate, B1+ field, and IEC safety limits.
B1 Field Mapping
Methods for measuring transmit field uniformity in MRI.

64 articles  ·  All articles include original SVG diagrams and links to related calculators