Compact Tri-Band Antenna with Double Winding Structures for 3G/4G/5G Base Station Applications

This paper presents a compact tri-band antenna with double winding structures for 3G/4G/5G base station applications. The proposed compact tri-band antenna design with double winding structure fed by a coplanar waveguide (CPW) reduces the installation space and mutual coupling between close frequency operation bands suitable for base band applications. The proposed antenna design can be configured for step-up and step-down transformer operation using double winding structures on either side of the central resonator with an ability to attain reversibility of transformer operation. The proposed compact tri-band antenna performance is evaluated for both with and without windings in the antenna structure. The proposed design without the winding structure achieves a dual band of operation whereas the design with a winding structure achieves tri-band operation with improved S11 performance and very less voltage standing wave ratio (VSWR). Two prototypes of tri-band ultra-wideband (UWB) antenna with double winding structures of high design specifications are fabricated and tested to validate the proposed design principle. The effectiveness of the projected design is evident from the excellent association between simulated and measured results. It is shown that the proposed design is very effective with low cost and the fabricated prototypes of the antenna with double winding structures are very compact with the dimensions of 18.6 X 15.6 mm2 achieving three frequency bands of operations at 2.9 GHz, 6.5 GHz, and 11.3 GHz with improved return loss < -10db and VSWR < 1.8.