A look at a novel Antenna design

Antennas are a key component for communications, both for receiving and transmitting, and there is a certain fascination with their design. It all started with the Hertzian dipole and its understanding and mathematical treatment. This presentation is based, in part, on modern mathematical tools as well as test equipment. As an example, Hallén wrote his famous integral equation to give an exact treatment of antenna current wave reflection at the end of a tube-shaped cylindrical antenna in 1956, but his first work on this subject probably goes back to 1938.
This equation enabled him to show that on a thin wire, the current distribution is approximately sinusoidal and propagates at nearly the speed of light. For this treatment, that is an important contribution We will learn here that by optimizing the effective length of a rod antenna it will become directional and will have a radiation pattern that provides gain. Antenna tuning is important for field operation. Dr. Tapan Sarkar, past IEEE AP-S president, Dr. Jim Breakall, Dr. Ajay K. Poddar, and I met several times in the past 30 years, discussed my pet project: positioning of antennas for portable operation, and we had many exchanges on this topic and sunspots and their effect on HF propagation. Dr. Tapan Sarkar passed away in 2020, but his scientific contributions in the field of Antenna and Propagation will be helpful to researchers and next-generation students in the field of wireless communication, especially applications in humanitarian technology. Now, Sun Cycle 25 is building an increasingly favoring radio operation in the HF band (1.5 to 30 MHz). There are military and other radio applications for 5 to 20-W battery-operated radios with whip antennas that make the radio portable. A whip antenna has no ground return, or proper counterpoise so it is not optimized for signal propagation. Thus, some users drag a wire behind them. This solution is not ideal. We explore optimizing antenna performance for HF, VHF, and UHF (spanning 1.5 to 512 MHz) manpacks and using an antenna tuning unit (ATU). Battery-operated manpacks with internal ATUs were used for testing, comparing internal ATUs with the performance obtained using external tuners. The necessary mathematical treatment for this case is provided here. Prof. Sarkar was involved with the modeling software WIPL-D and HOBBIES. Some anecdotes will be provided, with interactions with him on these, including numerous projects supported by IEEE SIGHT (Special interest Group on Humanitarian Technology) under the leadership of Dr. Ajay Poddar, Chair IEEE Humnatrain Activity Committee Inter-Society and Region Coordinator, IEEE AP, and MTT Societies. Dr. Tapan Sarkar and Dr. Ajay Poddar helped in establishing three IEEE awards for supporting students and young engineers working on Antenna and Microwave Theory and Technology: (1) IEEE Ulrich L. Rohde Innovative Conference Paper Awards on Antenna Measurements and Applications (This annual cash award and plaque, are given to the two most innovative conference papers presented at the annual topical meeting on Antenna Measurements and Applications), (2) IEEE Ulrich L. Rohde Innovative Conference Paper Awards on Computational Techniques in Electromagnetics (This annual cash award and plaque, are given to the two most innovative conference papers presented at the annual topical meeting on Computational Techniques in Electromagnetics), and (3) IEEE IEEE Ulrich L. Rohde Humanitarian Technical Field Project Award, USD 20,000 project award given annually by IEEE AP Society.

Speaker(s): Dr.Ulrich L. Rohde, Dr. James Breakall

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