Tunable wideband frequency and switching polarisation reconfiguration antenna for wireless applications

Abstract

In this article, a circular microstrip tunable wideband frequency and polarisation reconfigurable antenna are investigated. The wideband tunability is achieved by placing the four varactor diodes between circular microstrip patch and circular ring. The impedance bandwidth of 2.09–2.96 GHz (34.52%) is realised by tuning the capacitance value from 4.15 pF (0 V) to 0.94 pF (6 V). Both frequency tunability and polarisation reconfigurability are controlled in the antenna using the proposed cascaded branch line coupler feed network. The four single pole double throw and two dual in‐line package switches are used in the feed network to control the tunable impedance bandwidth of the antenna over a wideband from 1.25 to 2.95 GHz. The vertical linear polarisation and horizontal linear polarisation (H‐LP) are achieved by any one of the feed port excited in the antenna. Similarly, the right‐hand circular polarisation and left‐hand circular polarisation are realised by exciting both the feed ports in the antenna with±90° phase difference. The impedance bandwidth of proposed feed network is well matching with the tunable bandwidth of the patch antenna. Simulated and experimental verification results show good agreement.

Dual‐band frequency‐reconfigurable MIMO PIFA for LTE applications in mobile hand‐held devices

“…To reduce the effect of coupling between the main arm and supporting arms, a fixed capacitor is integrated into the antenna. To make the antenna as a frequency tuneable PIFA, the varactor diodes are used [24]. A 10 kΩ resistor is used in the LB and HB regions to bias the varactor diodes at the point P 1 and P 2 .…”

Efficiency‐based approach to quantifying ‘tuneability’ performance in frequency‐agile narrowband antennas

“…A search of published techniques for tuning compact and electrically small antennas in general terms revealed that tuneability is predominantly viewed in terms of tuneable input response (impedance matching from S 11 ). Of the sample of papers describing tuning techniques referenced [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], all either reported explicit tuning ranges in percentage terms with respect to a required S 11 threshold or provided the data required to do so. The aforementioned list gives a sample set of 18 papers, of which 15 were published in the last five years, thus the sample set is taken to be representative of contemporary reporting.…”

“…The trend for an increasing number of frequencies to be supported in one device has been showcased by the evolution of cellular communications, with the 9 bands specified for GSM [1] expanding to more than 50 to date in the present LTE-A specifications [2]. Other frequencyreconfigurable applications include public safety [3], cognitive radio [4], WLAN [5] and antennas combining multiple functions (e.g. [6] combining low-power WAN, GPS and Bluetooth).…”

“…A key metric of interest for such antennas is 'tuneability' or frequency agility, recording the range of frequencies that can be addressed by the tuneable antenna. A survey of the contemporary literature suggests that this assessment is almost always supported by a stated range of measured tuneable input responses S 11 [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. However, this makes no assessment of the radiation efficiency offered over the tuned range, reporting of which over a tuneable range was found to be much less widespread.…”

A wideband polarization reconfigurable antenna based on optical switches and C‐shaped radiator

“…Some polarization reconfigurable antennas that only work in LP mode or CP mode have been proposed in References . In References , linear polarization reconfigurable antenna has been proposed. They are the antennas with several switchable LP modes, with a relatively narrow impedance bandwidth.…”