A dual-band dual-pattern frequency-reconfigurable antenna

The functionality of a dual-band frequency-reconfigurable antenna based on a microstrip patch is extended toward independent tuning of its two operational bands. The antenna has distinct monopolar and broadside radiation patterns at its lower and upper bands, respectively, and a previous realization only allowed simultaneous tuning of the two bands. In this paper, a more sophisticated bias scheme with two DC bias voltages and four varactors is introduced to extend the principle toward independent control of the resonance frequencies of the two bands. An antenna prototype has been designed, fabricated, and validated with experiments. The results demonstrate that the antenna achieves independent relative tuning ranges of about 11% at both frequency bands.