Centre-fed dual band omnidirectional array antenna with electrical down tilt

摘要

A centre-fed dual band (3.5 GHz/5.8 GHz) omnidirectional microstrip array antenna for using in wimax applications is presented. Two distinct series fed back-to-back subarrays separated by a power divider are designated for these two bands. The proposed centre-fed structure reduces interference of two subarrays and provides a flexible progressive phase and so independent tilt angle control in dual bands. In addition, it is shown that compared to edge-fed dual band structure, the centre-fed structure makes the use of low permittivity substrates possible which are more appropriate for antenna radiation. The fabricated antenna can cover 3-3.7 GHz and 5.4-6.4 GHz frequency bands with S-11 < -10 dB. It also shows about 10 degrees down tilt in both frequency bands. (C) 2015 Elsevier GmbH. All rights reserved.