Description

This three-day course teaches the basics of antenna and antenna array theory. Fundamental concepts such as beam patterns, radiation resistance, polarization, gain/directivity, aperture size, reciprocity, and matching techniques are presented. Different types of antennas such as dipole, loop, patch, horn, dish, and helical antennas are discussed and compared and contrasted from a performance and applications standpoint. The locations of the reactive near-field, radiating near-field (Fresnel region), and far-field (Fraunhofer region) are described. The Friis transmission formula is presented with worked examples. Propagation effects are presented. Antenna arrays are discussed, and array factors for different types of distributions (e.g., uniform, binomial, and Tschebyscheff arrays) are analyzed giving insight to sidelobe levels, null locations, and beam broadening (as the array scans from broadside.) The end-fire condition is discussed. Beam steering is described using phase shifters and true-time delay devices. Problems such as grating lobes, beam squint, quantization errors, and scan blindness are presented. Antenna systems (transmit/receive) with active amplifiers are introduced. Finally, measurement techniques commonly used in anechoic chambers are outlined.

What You Will Learn:

• Basic antenna concepts that pertain to all antennas and antenna arrays.
• The appropriate antenna for your application.
• Factors that affect antenna array designs and antenna systems.
• Measurement techniques commonly used in anechoic chambers.

This course is invaluable to engineers seeking to work with experts in the field and for those desiring a deeper understanding of antenna concepts. At its completion, you will have a solid understanding of the appropriate antenna for your application and the technical difficulties you can expect to encounter as your design is brought from the conceptual stage to a working prototype.

Course Outline:

1. Basic concepts in antenna theory. Beam patterns, radiation resistance, polarization, gain/directivity, aperture size, reciprocity, and matching techniques.
2. RF Field Locations. Reactive near-field, radiating near-field (Fresnel region), far-field (Fraunhofer region) and the Friis transmission formula.
3. Types of antennas. Dipole, loop, patch, horn, dish, and helical antennas are discussed, compared, and contrasted from a performance/applications standpoint.
4. Propagation effects. Direct, sky, and ground waves. Diffraction and scattering.
5. Antenna arrays and array factors (e.g., uniform, binomial, and Tschebyscheff arrays).
6. Scanning from broadside. Sidelobe levels, null locations, and beam broadening. The end-fire condition. Problems such as grating lobes, beam squint, quantization errors, and scan blindness.
7. Beam steering. Phase shifters and true-time delay devices. Some commonly used components and delay devices (e.g., the Rotman lens) are compared.
8. Measurement techniques used in anechoic chambers. Pattern measurements, polarization patterns, gain comparison test, spinning dipole (for CP measurements). Items of concern relative to anechoic chambers such as the quality of the absorbent material, quiet zone, and measurement errors. Compact, outdoor, and near-field ranges.
9. Software simulation concepts. Discussion and distinction between: Finite Difference Time Domain (FDTD), the method of moments (MoM), and the Finite Element Method (FEM.) Some commercial codes that use these techniques.
10. Throughput and data rates. Various antennas are examined to quantify suitability for data transmission.
11. Special topics: The class can be tailored to meet the desired needs of the students.
12. Questions and answers.

Instructor(s):

Dr. Steven Weiss is a senior design engineer with the Army Research Lab in Adelphi, MD. He has a bachelor’s degree in Electrical Engineering from the Rochester Institute of Technology with master’s and Doctoral Degrees from The George Washington University. He has numerous publications in the IEEE on antenna theory. He teaches both introductory and advanced, graduate level courses at Johns Hopkins University on antenna systems as well as a class on electromagnetic theory. He is active in the IEEE and is a senior life member. Dr. Weiss worked at the Army Research Lab for over 36 years as the lead researcher for antennas and antenna-arrays before his retirement in March 2023. He is a member of the IEEE Antennas and Propagation Society, URSI Commissions A and B, and the Applied Computational Electromagnetics Society (ACES.) He is a licensed Professional Engineer in both Maryland and Delaware.