A frequency-reconfigurable antenna based on periodically loading ferroelectric MIM capacitors along a slot loop is designed, fabricated, and measured. The antenna is fabricated on a 430-µm-thick sapphire substrate with a total area of 1×1cm2
. The size of the slot loop is 2.5×2.5mm2
. By changing the bias voltage of the ferroelectric varactors from 0V to 7V, the resonant frequency of the varactor-loaded antenna can be tuned from 5.57GHz to 7.33GHz, corresponding to a tuning range of 27.3%, while keeping the return loss greater than 10dB. At 5.57GHz, the size of the slot loop is 0.046×0.046λ02
. When biased at 7V, the antenna gain is −10.8 dBi at 7.35GHz. Under 0-V bias, the Pin,1dB
of the tunable antenna is 18.8dBm at 5.6GHz.
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