Design Of Dual-port Filtering Antenna

The miniaturization and integration of wireless communication system has been a tendency recently.Components with different functions are co-designed into one device,providing new solution to realize miniaturization and integration.The antenna and filter are vital part of wireless communication system.The filtering antenna,which regarding the antenna and filter as a subsystem,decreases the number of ports to be matched.This method reduces not only the complexity of matching circuit but also the volume of the system.Two filtering antennas are integrated together and shared a radiator,which the volume of the system can be further reduced,making the structure more compact and realizing multiband function.Microstrip patch antenna(MPA)has many advantages,such as light in weight,simple in structure and easy for fabrication.In this paper,we designed four types of dual-port filtering antenna with microstrip patch antenna as the radiator.The filtering antenna can be designed compact and highly integrated due to the merits of the MPA.The following works are achieved in this paper:Firstly,a dual-port orthogonal polarized filtering antenna with low profile is introduced in this paper.The proposed antenna is achieved on single-layer printed circuit board(PCB)substrate.The profile of the proposed antenna is 1.6mm(0.018?₀).The radiation modes of the proposed antenna are TM₁₀ mode and TM₀₁ mode respectively.The isolation between the two ports can be improved by the frequency selectivity of the filtering antenna and orthogonal polarization.The bandwidth of the designed low profile dual-port filtering antenna are 2.48-2.72 GHz(9.2%)and 3.3-3.62 GHz(9.4%)respectively,the isolation between two ports is 42d B.Secondly,another dual-port filtering antenna is introduced in this paper.The proposed antenna is developed from connecting third-order bandpass filter to a square radiation patch etched with grid-shaped slots.The profile of the proposed antenna is 1.6mm(0.018?₀).The grid-shaped slots etched on the radiation patch have slow wave effect to reduce the radiation frequency and achieve the miniaturization for microstrip patch antenna.In the case of a limited area of metal ground,the miniaturized radiating patch can be used to leave larger space for the filtering feeding network.The bandwidth of two ports is the same,which is 2.50-2.68GHz(6.9%),and the isolation between two ports is 32d B.Thirdly,a dual-port quad-band filtering antenna is present in this paper.The frequency of TM₁₀mode and TM₀₁ mode are controlled by the dimension of the radiating patch.The TM₁₁ mode can be excited by selecting appropriate feeding location.The U-shaped slot is deliberately etched on the radiating patch to generate a new operation band.The filtering feeding network is achieved by placing the coupling slots etched on the metal ground orthogonally and loading the stub-loaded resonator(SLR).The proposed filtering antenna is developed by loading the feeding network to the dual-port quad-band MPA.The bandwidths of the proposed filtering antenna are 2.32-2.41 GHz,2.51-2.64 GHz,3.32-3.43GHz and 3.60-3.77 GHz respectively.The isolation between the two ports is 33d B.Fourthly,a dual-port filtering antenna with four bands individually controlled is designed in this paper.Based on the previous dual-port filtering antenna designed in the chapter 4,the TM₁₁ mode is replaced by a U-shaped slot resonant mode.The frequencies are separately controlled by the dimension of the radiation patch and two U-shaped slots.The proposed antenna has four independently operation bands,and the radiation pattern is optimized.The four bandwidths of the proposed dual-port quad-band filtering antenna are2.02-2.13GHz,2.35-2.48GHz,2.76-2.86GHz and 3.23-3.35GHz respectively.The isolation between the two ports in the whole band is 37d B.