Design of a low-cost broadband loaded dipole antenna for VHF/UHF frequency range

This study describes the concept and design of a low-cost super broadband dipole antenna with a passive matching network. The proposed dipole antenna is designed in three steps. First, a simple planar dipole antenna with six different loads and a balanced to unbalanced (Balun) transformer is designed by the genetic algorithm optimisation. The position and value of the loads are optimised to achieve an acceptable radiation pattern and voltage standing wave ratio (VSWR) over the desired frequency bandwidth. In the next step, the shape of the printed strip dipole antenna is optimised to improve the frequency response of the designed antenna. Finally, an LC network is added to the antenna feed point to reduce the antenna VSWR at low frequencies. The final dipole antenna has a length of 1.7 m and can operate over 30-1200 MHz with VSWR <3 and broadside gain >-10 dBi. The proposed antenna can easily be fabricated at a low cost via the printed circuit board technology. An industrial prototype of the proposed antenna is fabricated and measured. A good agreement between measurement and simulation results is observed.