A Broadband Unidirectional Multi-Dipole Antenna With Very Stable Beamwidth

A broadband multi-dipole antenna with stable beamwidth is presented. Through a rational design of position of dipoles and a reflector, an antenna with a wide impedance bandwidth, stable radiation pattern and nearly identical E- and H-planes is achieved. A laboratory model has been characterized experimentally. Experimental results agree well with simulations. Results show that an impedance bandwidth of 59.7% for SWR <; 1.5 from 1.55 to 2.87 GHz was achieved. Stable radiation pattern with 3 dB beamwidth 63.3 ± 2.9 degree at H-plane and 63.4 ± 2 degree at E-plane and an antenna gain of 9 ± 0.6 dBi was found over the operating frequencies.