On the Behaviour of Frequency-Reconfigurable Microstrip-line-fed Antenna with Hybrid Wide-Slot for Multiband Wireless Applications
In this paper, the multiband behaviour of the frequency-reconfigurable hybrid wide-slot antenna is studied. The proposed antenna consists of a hybrid wide-slot antenna, i.e., a combination of trapezium and semi-circular wide-slots. Both the wide-slots are merged with the help of three PIN diodes that help the proposed antenna to resonate in different resonating frequencies. When all the three PIN diodes are in ON-state, the proposed antenna resonates in three different frequency bands, i.e., 1.04-1.25 GHz (Band-I), 3.50-8.55 GHz (Band-II) and 10.84-13.16 GHz (Band-III). The peak gain in all Band-I, Band-II and Band-III frequency bands varies from 11.15-21.09 dB, 1.45-3.83 GHz and 0.78-3.71 dB, respectively. The overall size of the proposed hybrid wide-slot antenna is 25×32 mm2.
In recent years, the antenna researchers are mainly focusing on low-profile and compact antenna structures that support multiple wireless standards, i.e., possessing reconfigurability features. This will help in eradicating the problem of using multiple antenna structures in modern wireless devices and require less area for accommodating into them. In order to obtain the reconfigurability feature, several technologies including RF-MEMS switches , varactor and PIN diodes [2-4], switches with variable capacitances feature  and changing material properties  are being used. Out of them, PIN diodes are popular for integration with the antenna structures due to their low cost and small size.
B. Literature Survey
Several microstrip patch antennas with reconfigurable feature for multiband wireless applications have been already proposed in the literature. A reconfigurable patch antenna for WLAN/WiMAX wireless applications has been proposed in  where the parasitic strips are united with the main radiating patch with the help of PIN-diodes. Another reconfigurable probe-fed antenna with wide tuning range using varactor-diode is reported in . A Vivaldi antenna with frequency tenability is presented in  where circular ring slots (acting as band stop filter) are etched from the radiating geometry and are connected/disconnected using switches. A frequency and polarization reconfigurable antenna integrated with double-layered metamaterial is discussed in .
C. Proposed Design Novelty
In this paper, a hybrid wide-slot antenna with trapezoidal and semi-circular wide-slots is presented. Both the wide-slots are merged together with the help of PIN diodes. Our proposed antenna is different from the antenna structures