Resonant Cavity Theory and Its Applications Into Common-Mode Resonance Analysis and Suppression in Ultrawideband Phased Arrays

Le résumé fourni par la source

The common-mode (CM) resonance is a critical issue in ultrawideband (UWB) tightly coupled phased array systems. Traditional methods of CM signal analysis using circuit theories are not suitable here due to the distinctive characteristic of CM resonance. Thus, currently there is a lack of comprehensive theory for this issue, leading to inaccurate analysis and complex suppression strategies. To address this, this article proposes, for the first time, a resonant cavity theory to rigorously model and analyze the CM resonance in UWB tightly coupled arrays (TCAs). The proposed resonant cavity is constructed from an equivalent rectangular coaxial waveguide with hybrid boundaries of perfect electric conductor (PEC) and perfect magnetic conductor (PMC). To analyze the resonant cavity, decomposition of longitudinal field is performed, where field components are expanded into infinite Fourier series. Then boundary conditions are applied to derive discrete cavity resonant modes. It is demonstrated that CM resonance in UWB TCAs is equivalent to the dominant${\text {TM}}_{111}$resonant mode of the proposed resonant cavity. Based on this resonant cavity theory, two practical applications are illustrated. First, a method of accurately predicting CM resonant frequency is developed based on the equivalent circuit model of the cavity, realizing a prediction error below 1.14%. Second, a simple and effective strategy of suppressing CM resonance using CM inductors is introduced. Even- and odd-mode circuit analyses based on the resonant cavity theory are proposed to explain the suppression mechanism. To validate the proposed theory and suppression strategy, one$8\times 6$UWB TCA is designed and fabricated, which achieves effective CM suppression over 0.86–8.28 GHz (9.63:1) with wide-range scanning ability.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.