M. R. Hamid

A Compact Frequency-Reconfigurable Narrowband Microstrip Slot Antenna

A frequency-reconfigurable microstrip slot antenna is proposed. The antenna is capable of frequency switching at six different frequency bands between 2.2 and 4.75 GHz. Five RF p-i-n diode switches are positioned in the slot to achieve frequency reconfigurability. The feed line and the slot are bended to reduce 33% of the original size of the antenna. The biasing circuit is integrated into the ground plane to minimize the parasitic effects toward the performance of the antenna. Simulated and measured results are used to demonstrate the performance of the antenna. The simulated and measured return losses, together with the radiation patterns, are presented and compared.

Vivaldi Antenna With Integrated Switchable Band Pass Resonator

A novel reconfigurable wideband to narrowband Vivaldi antenna is presented. A single pair of ring slot resonators is located in the Vivaldi to realize frequency reconfiguration, maintaining the original size unchanged. The proposed antenna is capable of switching six different narrow pass bands within a wide operating band of 1-3 GHz, offering added prefiltering functionality. A fully functional prototype has been developed. PIN diode switches were employed at specific locations in the resonator to change its effective electrical length, hence forming different filter configurations. Antenna performance obtained from simulation and measurement results shows good agreement, which verifies the proposed design concepts. The antenna is potentially suitable for applications requiring dynamic band switching such as cognitive radio.

A Selective Frequency-Reconfigurable Antenna for Cognitive Radio Applications

This letter presents a selective frequency-reconfigurable antenna, suitable for cognitive radio applications. The proposed antenna is capable of switching between a wide operating band of 2.63-3.7 GHz and four different subbands, which allows using it for sensing the entire band and then adjusting its bandwidth to select the suitable sub-band and prefilter out the other ones. The antenna is composed of a radiating element in the form of an inverted U fed by a microstrip line on its upper side. In order to achieve a selective frequency reconfiguration, four horizontal slots with integrated p-i-n diode switches are incorporated in the ground plane to act as reconfigurable filter. Some of the switches are used to alter the antenna bandwidth, while the others are employed to shift the operating band by varying the electrical length of the middle slots. To present the work, both simulated and measured results are presented, and a good agreement is achieved.

Frequency-Reconfigurable Microstrip Patch-Slot Antenna

A frequency-reconfigurable microstrip patch switchable to slot antenna is proposed. The antenna is capable of frequency switching at nine different frequency bands between 1.98 and 3.59 GHz. The patch is resonating at 3.59 GHz, while the slot produces eight different operating frequencies between 1.98 and 3.41 GHz. Five RF p-i-n diode switches are positioned in the slot to achieve frequency reconfigurability. Simulated and measured results are used to demonstrate the performance of the antenna. The simulated and measured return losses, together with the radiation patterns, are presented.

Frequency reconfigurable microstrip patch-slot antenna with directional radiation pattern

In this paper, frequency reconfigurable slot-patch antenna with reflector at the back of an antenna is presented. The proposed antenna consists of a microstrip patch antenna and a microstrip slot antenna where the slot antenna is positioned at the ground plane underneath the patch. Three switches are placed in the slot. The antenna is capable to reconfigure up to six different frequency bands from 1.7 GHz to 3.5 GHz. The microstrip patch antenna produces three different frequency bands with directional radiation pattern while the microstrip slot antenna produces another three frequency bands with bidirectional radiation pattern. Due to the reflector placed at the back of the antenna, the radiation pattern is directional at all frequency bands. Simulated and measured results are used to demonstrate the performance of the antenna. The simulated and measured reflection coefficients and radiation patterns are presented and compared.

Frequency and pattern reconfigurable slot antenna

A novel frequency and pattern reconfigurable slot antenna is proposed. Slot antenna produces a bidirectional radiation pattern, thus a reflector is positioned behind of the antenna to generate a directional radiation pattern. Two switches are placed in the slot to produce three reconfigurable frequency bands: at 1.82 GHz, 1.93 GHz and 2.10 GHz. The introduction of four slits at the edge of the ground plane offers pattern reconfigurability. To tune the beam angles, three switches are inserted into each slit. By manipulating the phase of upper and lower slits in the ground plane, the proposed antenna is capable of reconfiguring its beam to three different angles at 0°, -15° and +15°. The simulated and measured results of reflection coefficient and radiation patterns are presented and compared.

FREQUENCY AND PATTERN RECONFIGURABLE YAGI ANTENNA

A novel frequency and pattern reconfigurable Yagi antenna is proposed. The antenna is formed by a driver, a reflector and two directors. The introduction of switches using a PIN diode at the arms of the driver element produces three switchable frequencies at 1.25 GHz, 1.85 GHz and 2.45 GHz. By controlling the switches at the directors and reflector, the radiation pattern can be configured to near omni-directional pattern or directional pattern at those three frequencies. Simulated and measured results are used to demonstrate the performance of the antenna. The simulated and measured return losses and the radiation patterns, are presented and compared. It was found that the gain of the antenna increases from 3.3 dB to 5 dB in a directional pattern, when compared to the near omni-directional pattern.

Frequency-Reconfigurable Rectangular Dielectric Resonator Antenna

A coplanar waveguide (CPW) reconfigurable dielectric resonator antenna (DRA) is presented and investigated. The DRA is capable of frequency tuning at three different frequency bands between 3.45 and 6.77 GHz. The overall size of the antenna is 50 × 57 mm2. The dielectric material is a rectangular block of ceramic with a permittivity of 15. Two switches, implemented using p-i-n diodes, are located on the lines of a feed network that is connected to the dielectric element. Single-band modes with impedance bandwidths of 8% and 16% are achieved by switching “on” one of three connecting feedline networks, whereas a wide band, with an impedance bandwidth of 65%, is achieved by switching “on” two connecting lines. Frequencies in the single band can be independently controlled using switch positions without affecting the wideband mode. The prototype has a low profile with a dielectric resonator thickness of 4 mm. The characteristics of this antenna were studied, and good agreement was found between the numerical and measured results.

A Compact Frequency-Reconfigurable Dielectric Resonator Antenna for LTE/WWAN and WLAN Applications

A compact frequency-reconfigurable dielectric resonator antenna (DRA) for LTE/WWAN and WLAN applications is investigated and presented. The proposed antenna provides the frequency tuning between 1.60 and 2.71 GHz. The design consists of four identical rectangular dielectric resonators with permittivity of 10 each and three p-i-n diode switches that are located on the feedline network between each of two dielectric resonators. The proposed antenna size is 20 ×36 ×5.57 mm3, which is suitable for mobile devices. The measurement and simulation results are applied to demonstrate the performance of the proposed antenna. From the measured results, it is found that the proposed antenna with acceptable performance provides four single-band modes with the impedance bandwidths of 17%, 11%, 14%, and 6%.

Frequency reconfigurable wide to narrow band monopole with slotted ground plane antenna

A frequency reconfigurable wide to narrow band antenna is presented. The proposed antenna is a combination of a monopole antenna (MA) and a microstrip slot antenna (MSA). The MA produces a wide frequency band from 1.66 to 4.93 GHz, and the MSA produces three different frequency bands resonating at 3.02, 3.89, and 4.56 GHz. Simulated and measured results are used to validate the performance of the antenna. The effects of using copper strip and PIN diode as switches in the simulation and measurement are demonstrated. The simulated and measured return losses, together with the radiation patterns, are presented and compared.