Compact structure with high TX-RX isolation for frequency domain duplexing on printed circuit boards

Abstract

When developing compact and lightweight antenna systems for unmanned aerial systems, achieving high isolation between transmit and receive signal paths is challenging. To address this issue, we demonstrate a prototype isolation design on a printed circuit board for a frequency division duplexed X band antenna system. Key components include a microstrip defected ground plane notch filter and a copper grating barrier that provides 20 dB higher isolation than free space separation between the transmit and receive antennas. The hardware provides at least 105 dB of transmit isolation into the receiver low noise amplifier in the transmit band. The proposed design is lighter and more compact than traditional machined metal waveguide isolation techniques used for ground-based systems yet achieves similar isolation performance.

Keywords:

• Electromagnetic isolation
• frequency division duplexing
• microwave printed circuit board
• x band
• small aircraft

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Jakob W. Kunzler  http://orcid.org/0000-0002-0404-6976

Additional information

Funding

This work was supported by a grant Y1504 from L3 Technologies to The Center for Unmanned Aircraft Systems (C-UAS).

Notes on contributors

Jakob W. Kunzler

Jakob W. Kunzler received his BS degree in Electrical Engineering at Brigham Young University (BYU), Provo, UT in 2017. After graduating, he was awarded the United States Department of Defense's SMART fellowship to continue his doctoral education at BYU. His research interests include the many disciplines associated with antenna array signal processing: analog and digital design for electronically steerable antennas implementing radar, communications, astronomical observations, and GPS services. Jakob has served as president and service coordinator of BYU's chapter of IEEE's Eta Kappa Nu honor society. After obtaining his doctoral degree at BYU, Jakob will continue his career as civilian research scientist at the Naval Information Warfare Center in Charleston, South Carolina.

Jacob M. Bartschi

Jacob M. Bartschi is an undergraduate research assistant at Brigham Young University studying Electrical Engineering and expects to graduate in April 2020. His research interests include electromagnetics and RF/microwave hardware. Jacob plans to pursue a Master's degree in Electrical Engineering after graduation.

Karl F. Warnick

Karl F. Warnick (SM'04, F'13) received the BS degree in Electrical Engineering and Mathematics and the PhD degree in Electrical Engineering from Brigham Young University (BYU), Provo, UT, in 1994 and 1997, respectively. From 1998 to 2000, he was a Postdoctoral Research Associate and Visiting Assistant Professor in the Center for Computational Electromagnetics at the University of Illinois at Urbana-Champaign. Since 2000, he has been a faculty member in the Department of Electrical and Computer Engineering at BYU, where he is currently a Professor. Dr Warnick has published many books, scientific articles and conference papers on electromagnetic theory, numerical methods, antenna applications, and high sensitivity phased arrays for satellite communications and radio astronomy.