Module 2 — Antenna Types, Simulation, and Measurement#

ECE 444 · Module 02

Antenna Types, Simulation, and Measurement

Theory is cheap. Build it, simulate it, then measure it.

Lessons 7–14 · Antennas, Phased Arrays, and Radar Systems · Dr. Neil Rogers

Where This Module Goes

Module 1 described any radiator in the abstract. This module meets the real families — dipoles, loops, monopoles, patches, slots, horns, reflectors, Yagis — and asks what each one is actually good for.

Then it puts numbers on them twice over: once in a simulator, once on the bench. When those two disagree, one of them is wrong, and finding out which is the skill.

You will simulate a dipole and predict its impedance, then walk to the VNA and measure the same antenna. Expect the two to differ. The gap between a model and a measurement is where engineering judgment lives, and it is far more useful than either number on its own.

Measurement Comes Early

The measurement block sits at Lessons 9–11, ahead of the remaining antenna families, because the midterm project is a pattern-measurement campaign and it is due 2 Oct. Learning the range and the analyzer first buys you eleven lessons of bench time instead of six.

The order costs you something and it is worth naming. When you measure in Lesson 11 you will have met the dipole and not yet met the patch, the horn, or the reflector, so the antenna you characterize is a simpler one than it would have been. Lessons 12–14 then read differently: every gain figure and every pattern in them is a claim you already know how to check, and several of them are claims you will want to check for your project report.

Learning Objectives 2.1-2.3

  1. I can describe the radiation behavior of simple resonant antennas (isotropic radiator, half-wave dipole, monopole, loop) and calculate their gain and impedance.
  2. I can simulate a dipole antenna using an EM simulation tool and interpret the results against analytical predictions.
  3. I can describe the radiation mechanism, pattern, and typical use cases for patch, slot, and horn antennas.

Learning Objectives 2.4-2.6

  1. I can describe how reflectors, Yagi-Uda antennas, and arrays achieve high gain, explain how a log-periodic antenna trades gain for bandwidth, and select an appropriate high-gain antenna for a given application.
  2. I can explain the theory behind antenna pattern measurement, including anechoic chambers, near-field to far-field transformations, and standard gain horns.
  3. I can measure the impedance and S-parameters of an antenna using a vector network analyzer and interpret the results.

Learning Objective 2.7

  1. I can measure the radiation pattern of an antenna and extract gain, beamwidth, sidelobe level, and polarization from the data.

Where This Is Going

Module 3 stops treating an antenna as one object. Put several in a row, control the phase of each, and the pattern becomes something you steer rather than something you accept.

Everything you measure here — pattern, gain, beamwidth, sidelobe level — is what you will steer there.