Integrated antenna with a via-hole balun and hairpin resonator narrow band pass filter for microwave communications

In this paper, three-dimension (3-D) finite-difference time-domain (FDTD) simulation of a 2.4-, 5.2-, and 5.8-GHz antenna and hairpin resonators are presented. Integrated simulator is used to design the resonator and to calculate the coupling coefficients. A cross-coupled planar microwave elliptic function filter using coupled microstrip miniaturized hairpin resonators is designed and implemented. To construct band pass filter, parallel and series resonance characteristics of electrical, magnetic or mixed coupling are discussed. Theoretical analysis is used to illustrate the different coupling functions. The Berenger perfectly matched layer (PML) absorbing boundary condition is used for the FDTD computation. The proposed reduced short circuit plate (RSC) and lower resonant frequency (LRF) for antenna design with a microstrip via-hole balun is designed and fabricated on a laser direct structuring (LDS) substrate.