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Contents

Electromagnetic Theory

Vector Analysis

Cartesian Coordinate System Cylindrical Coordinate System Spherical Coordinate System Vector Addition and Subtraction Dot Product Cross Product Scalar Triple Product Gradient Divergence Curl Laplacian Operator Divergence Theorem Stokes Theorem Helmholtz Theorem

Electrostatics

Coulomb Law Electric Field Intensity Electric Field of Line Charge Electric Field of Surface Charge Electric Flux Density Gauss Law Gauss Law Applications Electric Potential Potential and Field Relationship Electric Dipole Polarization Boundary Conditions Electrostatics Capacitance Energy Stored in Electric Field Poisson and Laplace Equations

Magnetostatics

Biot-Savart Law Magnetic Field of Infinite Wire Magnetic Field of Circular Loop Ampere Circuital Law Ampere Law Applications Magnetic Flux Density Magnetic Force on Current Lorentz Force Magnetic Materials Boundary Conditions Magnetostatics Inductance Inductance Calculations Magnetic Energy

Maxwell Equations

Faraday Law of Induction Lenz Law Displacement Current Maxwell Equations Integral Form Maxwell Equations Differential Form Maxwell Equations in Phasor Form Boundary Conditions General

Wave Propagation

Wave Equation Derivation Uniform Plane Wave Phase Velocity and Wavelength Intrinsic Impedance Poynting Vector and Power Flow Wave Propagation in Lossy Media Skin Effect Linear Polarization Circular Polarization Elliptical Polarization Reflection at Normal Incidence Reflection at Oblique Incidence Total Internal Reflection

Transmission Lines

Transmission Line Parameters Transmission Line Equations Characteristic Impedance Reflection Coefficient VSWR Input Impedance of TL Lossless Transmission Line Quarter Wave Transformer Smith Chart Basics Smith Chart Applications Single Stub Matching Double Stub Matching

Antennas

Antenna Fundamentals Radiation Pattern Antenna Parameters Hertzian Dipole Half Wave Dipole Quarter Wave Monopole Antenna Arrays Friis Transmission Equation Yagi-Uda Antenna Parabolic Reflector Antenna

Other Topics

Other Subjects

Analog Electronics Digital Electronics Signals & Systems Control Systems Digital Communication Analog Communication Network Analysis Microprocessors VLSI Design Verilog HDL Power Electronics Embedded Systems DSP Electronic Devices

Section Progress67%

8 of 12 articles

Quarter Wave Transformer

Lambda/4 matching, Zin = Z0²/ZL, impedance transformation.

Updated: 19 March 2026

5 min read

#Electromagnetics

Quarter Wave Transformer

Test your mastery of the lambda/4 matching technique and impedance transformation.

Question 1 of 3

Q1.A quarter-wave transformer is used to match a 100-ohm load to a 25-ohm feed line. What must be the characteristic impedance of the transformer section?

Related Articles

Quarter Wave Monopole

Ground plane antenna, 36.5 ohm, vertical polarization.

5 min read

Characteristic Impedance

Z0 = sqrt((R+jwL)/(G+jwC)), lossless Z0 = sqrt(L/C).

6 min read

VSWR

Voltage standing wave ratio, relation to reflection coefficient.

7 min read

Reflection Coefficient

Gamma = (ZL-Z0)/(ZL+Z0), magnitude and phase.

5 min read

Transmission Line Equations

Telegrapher equations, voltage and current waves.

6 min read

Lossless Transmission Line

Smith Chart Basics