A Wide Stopband Filtering DDPA With Metal Vias and Metal Strips
Dong‐Sheng La, Hao Liu, Run-Long Wang, Kang Tian, Meijun Qu
Abstract
In this communication, a wide stopband filtering dense dielectric patch (DDP) antenna (DDPA) with metal vias and metal strips is proposed. The feeding structure consists of a short-circuited microstrip line and a separated slot. Based on this feeding structure, the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$TE_{11}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$TE_{12}$ </tex-math></inline-formula> modes of DDP are successfully excited. The electric field region of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$TE_{11}$ </tex-math></inline-formula> mode is much smaller than the physical region of DDP. The electric field region of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$TE_{12}$ </tex-math></inline-formula> mode is basically the same as the physical region of DDP. The resonant frequency of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$TE_{11}$ </tex-math></inline-formula> mode is close to the resonant frequency of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$TE_{12}$ </tex-math></inline-formula> mode and the passband is formed. Two semicircular DDPs are etched, and two semicircular metal strips are introduced to generate the low-frequency radiation null. Then, ten metal vias are loaded inside the DDP to further change the resonant frequencies of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$TE_{11}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$TE_{12}$ </tex-math></inline-formula> modes. The ten metal vias also adjust the H-plane radiation pattern of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$TE_{12}$ </tex-math></inline-formula> mode and improve the impedance matching of the proposed filtering DDPA. The measured results are basically consistent with the simulated ones. The relative impedance bandwidth is 4.2% (3.08–3.21 GHz). The low-frequency stopband range is 0.1–3.05 GHz, and the high-frequency stopband range is 3.38–7.0 GHz. The filtering DDPA has good sideband selectivity and wide stopband.