A frequency-reconfigurable slot loop antenna using ferroelectric MIM capacitors

Abstract

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-m-thick sapphire substrate with a total area of 1×1 cm 2 . The size of the slot loop is 2.5×2.5 mm 2 . By changing the bias voltage of the ferroelectric varactors from 0 V to 7 V, the resonant frequency of the varactor-loaded antenna can be tuned from 5.57 GHz to 7.33 GHz, corresponding to a tuning range of 27.3%, while keeping the return loss greater than 10 dB. At 5.57 GHz, the size of the slot loop is 0.046×0.046 0 2 . When biased at 7 V, the antenna gain is À10.8 dBi at 7.35 GHz. Under 0-V bias, the P in,1 dB of the tunable antenna is 18.8 dBm at 5.6 GHz.

Frequency-Tunable Slot-Loop Antenna Based on KNN Ferroelectric Interdigitated Varactors

“…The antenna was designed to operate at Ku-band. Its layout (inspired from [8], [9]) and cross-section view are reported in Fig. 1a and 1b respectively.…”

“…Li et al introduced a slot-loop miniature tunable antenna with BST-based interdigitated varactors and operating close to 15 GHz [8]; such antenna exhibited a 1%-frequency tunability rate under 195 kV/cm dc bias electric field. To increase the tunability rate, this group proposed slot-loop miniature tunable antennas based on MIM varactors operating at C-and X-bands [9], [10]. MIM capacitors have been often exploited [9]- [13] as this configuration helps to increase the applied external static electric field, thus leading to an increase of the tunability rate up to 27.3% and 30.6%, respectively (Table I).…”

“…To increase the tunability rate, this group proposed slot-loop miniature tunable antennas based on MIM varactors operating at C-and X-bands [9], [10]. MIM capacitors have been often exploited [9]- [13] as this configuration helps to increase the applied external static electric field, thus leading to an increase of the tunability rate up to 27.3% and 30.6%, respectively (Table I). However, these antennas usually suffered from very low gain values and such MIM capacitors are really challenging to fabricate.…”

Wideband frequency reconfigurable antenna array

“…To achieve this performance, many frequency reconfigurable antennas [1,2,3,4,5,6,7,8] and reconfigurable frequency selective surfaces [9,10] with wide tuning ratio were published. They can use switching components such as PIN diodes, varactor diodes, and microelectromechanical systems (MEMS) to provide multi-band operation more easily.…”

Frequency Reconfigurable Circular Patch Antenna with an Arc-Shaped Slot Ground Controlled by PIN Diodes

“…In [4], a varactor-tuned frequency reconfigurable antenna based on a dual frequency microstrip antenna is presented, and a high tuning frequency range is achieved from 1.037 GHz to 1.485 GHz when the bias voltage is varied from 0 to −30 V. And in [5], a continuously tunable frequency reconfigurable antenna based on a circular monopolar patch antenna using varactor is presented. Because of the advantages of low biasing voltage, high tuning speed (1-100 ns), high power handling capability, high reliability, and extremely low cost, PIN diodes based frequency reconfigurable antenna has attracted tremendous research interest [6][7][8][9][10][11][12]. Recently, lots of frequency reconfigurable antennas based on UWB antenna [3], circular monopolar patch antenna [5], slot antennas [7][8][9][10][11], bow-tie antenna [12], and PIFA [13] were proposed for multiband wireless communication applications like low frequency LTE band (699-862 MHz), high frequency LTE band (2496-2690 MHz), Bluetooth (2400-2480 MHz), WLAN (5.15-5.825 GHz), WiMAX (2500-2690 MHz), and so forth.…”