Radiation Pattern Characteristics of a Wideband Novel Modified Archimedean Spiral Antenna Array Covering DCS/PCS/WLAN and LTE Wireless Communication Bands

Radiation pattern characteristics of an array antenna are presented, which employs a wideband novel modified Archimedean spiral antenna reported in a previous work as the radiating elements. The antenna has no ground plane, hence its radiation patterns are bidirectional as it radiates simultaneously in both directions. The sum-mode and difference-mode excitations of the 2 × 2 array configuration are included. The sum-mode excitation of the 2 × 2 array with dimensions 150 × 150 × 0.8 mm
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covers the frequency bands DCS (1710-1880 MHz), PCS (1850-1990 MHz), WLAN (2.3-2.5 GHz), and LTE Band 7 (2.5-2.6 GHz), all with circularly polarized radiation patterns and gain at broadside angle varying between 5-9 dBic. A prototype antenna was fabricated and experimentally verified for the sum mode for both the impedance matching and radiation pattern characteristics. This antenna can also be used in monopulse radar tracking and transmit/receive communications after cavity backing.