# Nonreciprocal Yagi-Uda Filtering Antennas

## TL;DR

This paper introduces a compact, nonreciprocal filtering antenna using temporal modulation, achieving high isolation and minimal gain loss, suitable for integration in communication and sensing systems.

## Contribution

It presents a novel, integrated nonreciprocal filtering antenna design based on temporal modulation and microstrip resonators, demonstrating high isolation at 2.4 GHz.

## Key findings

- Isolation greater than 20 dB achieved
- Gain drop of only 3.5 dB compared to reference
- Successful prototype testing at 2.4 GHz

## Abstract

This paper proposes a novel and compact nonreciprocal filtering antenna based on temporal modulation. The device is composed of a third order filtering section integrated into a Yagi-Uda planar printed antenna. Strong nonreciprocity in transmission and reception is achieved at the same operation frequency by time-modulating the resonators of the filtering section. These resonators are implemented as quarter wavelength microstrip lines terminated with varactors located on the ground plane. Such plane is also employed as a reflector for the Yagi-Uda antenna and to host the coplanar waveguides that feed low-frequency signals to the varactors, thus leading to a very compact design. A prototype is manufactured and successfully tested at 2.4 GHz, showing isolation greater than 20 dB between transmission and reception modes in both E- and H- planes for all directions in space and a gain drop of only 3.5 dB compared to a reference antenna. The proposed devices can easily be integrated with other electronic circuits and may find exciting applications in communication, radar, and sensing systems.

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Source: https://tomesphere.com/paper/1906.06418