Co-design of a filtering antenna based on multilayer structure

In this paper, a co-design of filtering antenna based on multilayer structure is proposed for modern wireless communication systems. The filtering antenna system consists of a filtering network partly designed on two dielectric substrates and a Г-shaped antenna, which performs as both a radiator and the last order of the filter. An effective co-design method based on parameter extraction for impedance matching can significantly reduce the optimization time. Furthermore, a slot is grooved on the common ground, which is shared by the antenna and the filter to realize the feeding of the resonator. A prototype of the filtering antenna was fabricated and measured, and a good agreement is achieved. The tested results show that the filtering antenna features a 2.7% bandwidth, 2.2 dBi gain at 2.6 GHz and −20 dB out of band rejection at 5 × f₀. The size of the design is 0.29λ_g × 0.23λ_g.