Dual-Polarized Filtering Magnetoelectric Dipole Antenna Utilizing Intrinsic Highpass Filter Network and Integrated Lowpass Filter Network

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.