Wideband Loop Antenna With Electronically Switchable Circular Polarization

This letter presents a novel printed antenna with wide bandwidth, high gain, and reconfigurable circular polarizations. A loop antenna is printed on both sides of a dielectric substrate: A dual-p-i-n-diode loaded loop is printed on one side, while a dual-gap loaded smaller loop is printed on the other side. By controlling the on–off states of the p-i-n diodes, the polarization of the proposed antenna can be switched electronically to right-hand circular polarization (RHCP) or left-hand circular polarization (LHCP) over a wideband frequency range. A prototype is fabricated and measured to verify the performance of the antenna. The measured results indicate that the antenna achieves an impedance bandwidth of over 30%, and a 3-dB axial-ratio (AR) bandwidth of 12.7% and 14.9% for RHCP and LHCP, respectively. The measured gain is around 8 dBic for the LHCP state and 7 dBic for the RHCP state. Due to the advantages of wide overlapped bandwidth, simple feeding structure, and high gain, this antenna is promising for applications in dual-CP wireless communication systems.

[1]  Fan Yang,et al.  Circular Polarization Reconfigurable Wideband E-Shaped Patch Antenna for Wireless Applications , 2013, IEEE Transactions on Antennas and Propagation.

[2]  Chang-Hong Liang,et al.  Effect of Antenna Polarization Diversity on MIMO System Capacity , 2010, IEEE Antennas and Wireless Propagation Letters.

[3]  Chang-Hong Liang,et al.  Polarization Reconfigurable U-Slot Patch Antenna , 2010, IEEE Transactions on Antennas and Propagation.

[4]  Y. Rahmat-Samii,et al.  A reconfigurable patch antenna using switchable slots for circular polarization diversity , 2002, IEEE Microwave and Wireless Components Letters.

[5]  Kwai-Man Luk,et al.  A Wideband L-Probes Fed Circularly-Polarized Reconfigurable Microstrip Patch Antenna , 2008, IEEE Transactions on Antennas and Propagation.

[6]  J. Laskar,et al.  Determination of reactance loading for circularly polarized circular loop antennas with a uniform traveling-wave current distribution , 2005, IEEE Transactions on Antennas and Propagation.

[7]  Vincent Fusco,et al.  Circularly polarized open-loop antenna , 2003 .

[8]  S. Gao,et al.  Polarization-agile antennas , 2006, IEEE Antennas and Propagation Magazine.

[9]  R. Bawer,et al.  A Printed Circuit Balun for Use with Spiral Antennas , 1960 .

[10]  Vincent F. Fusco,et al.  Understanding and measuring circular polarization , 2003, IEEE Trans. Educ..

[11]  S. X.  Circularly Polarized Antennas , 2014 .

[12]  E. Ayanoglu,et al.  A MIMO System With Multifunctional Reconfigurable Antennas , 2006, IEEE Antennas and Wireless Propagation Letters.

[13]  Kai Chang,et al.  A Novel Reconfigurable Microstrip Antenna With Switchable Circular Polarization , 2007, IEEE Antennas and Wireless Propagation Letters.

[14]  J. Laskar,et al.  Investigation of circularly polarized loop antennas with a parasitic element for bandwidth enhancement , 2005, IEEE Transactions on Antennas and Propagation.

[15]  Manos M. Tentzeris,et al.  Bandwidth and gain improvement of a circularly polarized dual-rhombic loop antenna , 2006, IEEE Antennas and Wireless Propagation Letters.

[16]  H. Scott,et al.  Polarization agile circular wire loop antenna , 2002, IEEE Antennas and Wireless Propagation Letters.