In-Band Full-Duplex Filtering Antenna Arrays Using High-Order Mode Cavity Resonators

Institute of Electrical and Electronics Engineers (IEEE)
Publication Type:
Journal Article
IEEE Transactions on Microwave Theory and Techniques, 2022, PP, (99), pp. 1-10
Issue Date:
Full metadata record
In this article, a series of narrowband and wideband in-band full-duplex (IBFD) filtering antenna arrays (FAAs) using cavity-based high-order modes are investigated. It is found that the pairs of degenerate high-order modes in a single cavity resonator, TM $_{1n0}$ and TM $_{n10}$ ( $n$ is even), are suitable for the IBFD FAA designs due to their advantages: 1) in-phase and same amplitude for each magnetic loop, which helps to enhance the gain, and 2) the modal orthogonality, which guarantees the isolation and cross-polarization level between two channels. The higher order response can be achieved by cascading more high-order mode resonators with the required external quality factor ( $Q_{e})$ and coupling coefficient ( $K)$ . For proof of concept, two types of full-duplex waveguide arrays are implemented and tested. First, a second-order IBFD FAA with 6 $\times$ 5 elements, using a pair of degenerate modes TM $_{610}$ and TM $_{160}$ , is designed with 1% overlapped 10-dB bandwidth and 18.4-dBi realized gain within the passband. The method to improve realized gain and isolation level without increasing any circuit volume is also presented. Second, a fifth-order IBFD FAA using TM $_{410}$ and TM $_{140}$ modes is implemented with an overlapped 10-dB bandwidth of 15.6% and a realized gain of 12.5 dBi. The measured isolation between the two channels is better than 40.4 dB. An excellent agreement between simulated and measured results verifies that the proposed design methodology is feasible for designing high-order mode IBFD FAA.
Please use this identifier to cite or link to this item: