A planar VHF reconfigurable slot antenna

This paper presents a novel electronically tunable slot antenna. The design is based on a resonant slot structure loaded with a series of PIN diode switches. The tuning of the operating frequency is realized by varying the electrical length of the antenna, which is controlled by the DC bias voltages of the switches. The fabricated antenna is capable of resonating at four different frequencies ranging from 550 to 900 MHz. Very good matching is achieved for all resonant frequencies without the need for any special matching network. Additionally, it is demonstrated that the radiation pattern, efficiency and polarization remain essentially unaffected by the frequency tuning.