Wideband Filtering and Circularly Polarized Antenna Arrays With Self-Packaged Multilayer Suspended Substrate Technique

In this article, a new butterfly-shaped filtering antenna array with Chebyshev filtering response, and a new wideband circularly polarized antenna array have been proposed, both using self-packaged multilayer suspended substrate technique. The filtering antenna array integrates the functions of a bandpass filter, a power divider, and a $2\times 2$ antenna array by using multiple coupling resonators, while the circularly polarized antenna array is constructed by the wide slot structure using sequential rotation technique with 90° phase difference on neighboring antenna unit. Measured by vector network analyzer and spherical multiprobe test system, the filtering antenna array has been demonstrated with an impedance bandwidth of 11.8%, a favorable gain of 10.5 dBi, and a pair of gain zeros; meanwhile, the circularly polarized antenna array has a measured fractional impedance bandwidth of 60.9%, a maximum gain of 10.2 dBi, and a wide 3 dB axial ratio bandwidth covering 3.18–5.8 GHz. The measured results agree with the simulations. The proposed works integrate the advantages of suspended coplanar waveguide (SCPW), multiple resonators including microstrip patches and wide slots, which not only improve the design flexibility but also achieve wideband and favorable gain. While the feeding network and the radiation elements can be protected by the self-packaged construction.