Wideband dual-layer patch antenna fed by a modified L-strip

Abstract

Abstract-A wideband patch antenna is proposed. By using the dual-layer patch configuration and modified L-strip feed technique, the impedance bandwidth of the patch antenna for VSWR<1.2 is broadened to 22% with respect to 900 MHz, which is superior to the other available patch antennas. In addition, by means of the modified L-shaped strip, the high cross polarization levels of the proposed antenna are suppressed effectively. Simulation results are compared with the measurements, and a good agreement is obtained. The measurements show that the antenna has a low crosspolarization level (<-20dB) and an acceptable gain level (~9dBi) across the operating bandwidth. At last, a parametric study and a design guideline of the proposed antenna are also presented to facilitate the design and optimization processes for engineers. probe-fed stacked patch for ultra-wideband (UWB) applications has resulted in 102.36% bandwidth [7]. In light of the foregoing survey, using the VSWR<1.2 requirement, the impedance bandwidth of the available patch antennas is still narrow (less than 10%). As we known, the VSWR of the antennas for DAB (Digital Audio Broadcasting) and DVB (Digital Video Broadcasting) transmission system is needed to be less than 1.2. So the colossal growth of DAB and DVB necessitates the development in the VSWR<1.2 bandwidth broadening techniques.Another issue is that the foregoing techniques [1]- [7] have the disadvantage of high crosspolarization levels. In particular, the beam widths with the cross-polarization levels 20 dB lower than co-polarization levels are only few degrees near the boresight direction in H-plane. This is evidently a

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