BANDWIDTH IMPROVEMENT OF REFLECTARRAY ANTENNAS USING CLOSELY SPACED ELEMENTS

A bandwidth improvement method in re∞ectarray anten- nas by using closely space elements, i.e., unit-cell sizes smaller than ‚/2, has been investigated both numerically and experimentally in this paper. A new deflnition of phase error has been introduced to analyze the broadband mechanism of closely spaced phasing elements. Through full wave EM simulations, it is revealed that closely spaced elements achieve a smaller phase error over the band. Based on these theoretical studies two Ka-band re∞ectarrays were fabricated and their performance was measured across the frequency range of 30 to 34GHz. It is demonstrated that the re∞ectarray designed with closely spaced elements achieves a notable improvement in gain bandwidth perfor- mance.

[1]  Fan Yang,et al.  Electromagnetic Band Gap Structures in Antenna Engineering , 2008 .

[2]  E. Carrasco,et al.  Reflectarray Element Based on Aperture-Coupled Patches With Slots and Lines of Variable Length , 2007, IEEE Transactions on Antennas and Propagation.

[3]  W. Shao,et al.  Novel Broadband Reflectarray Antenna with Compound-Cross-Loop Elements for Millimeter-wave Application , 2007 .

[4]  D. Pozar.  Bandwidth of reflectarrays , 2003 .

[5]  S. Costanzo,et al.  Aperture-Coupled Reflectarrays with Enhanced Bandwidth Features , 2008 .

[6]  R. Pogorzelski,et al.  A Ka-band microstrip reflectarray with elements having variable rotation angles , 1998 .

[7]  Marek E. Bialkowski,et al.  BANDWIDTH CONSIDERATIONS FOR A MICROSTRIP REFLECTARRAY , 2008 .

[8]  J. Encinar.  Design of two-layer printed reflectarrays using patches of variable size , 2001 .

[9]  J. Encinar,et al.  Bandwidth Improvement in Large Reflectarrays by Using True-Time Delay , 2008, IEEE Transactions on Antennas and Propagation.

[10]  David M. Pozar,et al.  Wideband reflectarrays using artificial impedance surfaces , 2007 .

[11]  D. Pozar,et al.  Design of millimeter wave microstrip reflectarrays , 1997 .

[12]  John Huang,et al.  Bandwidth study of microstrip reflectarray and a novel phased reflectarray concept , 1995, IEEE Antennas and Propagation Society International Symposium. 1995 Digest.

[13]  J. A. Encinar,et al.  94 GHz Dual-Reflector Antenna With Reflectarray Subreflector , 2009, IEEE Transactions on Antennas and Propagation.

[14]  M. Cuhaci,et al.  A broadband reflectarray antenna with double square rings , 2006 .

[15]  Yahya Rahmat-Samii,et al.  Electromagnetic Band Gap Structures in Antenna Engineering: Frontmatter , 2008 .

[16]  S. Costanzo,et al.  Bandwidth enhancement of aperture-coupled reflectarrays , 2006 .