Dual-Polarized Filtering Magnetoelectric Dipole Antenna Utilizing Intrinsic Highpass Filter Network and Integrated Lowpass Filter Network
Yao Zhang, Xiu Yin Zhang, Qing Liu
Abstract
This article presents an effective design method to integrate bandpass filtering response into an aperture-fed dual-polarized magnetoelectric dipole (ME-dipole) antenna. The antenna is composed of a traditional ME-dipole radiator and a modified aperture-coupled feeding structure. In one aspect, highpass filtering radiation response is realized by approximating the antenna radiator as a highpass filter network. In another aspect, by developing an improved aperture-coupled feeding structure with lowpass filter characteristics, the antenna obtains lowpass filtering radiation response. As a result, bandpass filtering radiation response is achieved. Since no intricate filter resonators are used, the in-band antenna gains are not degraded. The highpass/lowpass filter networks are studied and specific radiation nulls generated by the two networks are analyzed. For demonstration, a single-polarized model is presented first and its working mechanism is studied in detail. It realizes a 78.6% impedance bandwidth, flat in-band gains of 7.5–7.8 dBi, and more than 22 dB out-of-band radiation suppression level. Then, based on the same methodology, a dual-polarized antenna model i developed with 69.3% operating bandwidth, 7.1–9.3 dBi measured in-band gains, and integrated bandpass filtering radiation response.