Low-Profile Dual-Band Band Filtering Patch Antenna and Its Application to LTE MIMO System
Abstract: This paper presents a low-profile low dual-band band filtering antenna element and its application to long-term term evolution (LTE) multiple-input multiple input multiple multiple-output (MIMO) system for wireless customer premise equipments (CPEs). The proposed element consists of two separate te U U-shaped shaped patches operating at different frequencies and a multistub microstrip feed line. For size miniaturization, the smaller U-shaped U patch is embedded in the larger one. In addition, the multistub feed line can generate two controllable resonant modes modes as well as two nulls in realized gain at the boresight direction. Since the modes of the patches and multistub feed line can be controlled individually, the two operating bands can be tuned to desired frequencies. Also, the radiation nulls in boresight gain can be controlled, high rollroll off rate and out-of-band band radiation rejection levels are thus obtained. For demonstration, a low profile (0.009Îť0) dual-band band filtering antenna element operating at 1.9 and 2.6 GHz for TD TD-LTE LTE applications (B39 and B38-bands) B38 is implemented. Dual-band band bandpass responses and four radiation nulls are observed in the experiment. Measured in-band in band gains are 6.7 and 7.3 dBi, whereas out-of-band band gains are less than -10 10 dBi. Based on this element, a four-element four MIMO antenna is furthe furtherr designed for LTE CPEs, where low profile and high integration of multiple components are required. A low mutual coupling of less