BANDWIDTH CONSIDERATIONS FOR A MICROSTRIP REFLECTARRAY

The paper describes a theoretical investigation into a limited bandwidth operation of a microstrip reflectarray. Two main factors limiting the bandwidth are considered. One is related to the requirement of phase compensation to convert a spherical wavefront launched by a feed into a planar wavefront. The other one is linked to the limited phasing range of microstrip antenna elements. The two factors contribute to the reflectarray phasing errors that in turn reduce its gain as a function of frequency. Simple formulas for an upper bound of gain bandwidth are derived, assuming the phase compensation by the elements is independent of frequency changes and verified against the results produced by other researchers. It is shown that the phase errors incurred in the path equalization to obtain conversion from spherical to planar wavefronts have a more profound effect on the reduction of operational bandwidth of the reflectarray than the phase truncation implemented on the required phase from each element.

[1]  T. A. Metzler,et al.  Analysis of a reflectarray antenna using microstrip patches of variable size , 1993 .

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

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

[4]  J. Huang,et al.  Microstrip reflectarray with elements having variable rotation angles , 1997, IEEE Antennas and Propagation Society International Symposium 1997. Digest.

[5]  Maurizio Bozzi,et al.  Performance comparison of different element shapes used in printed reflectarrays , 2003 .

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

[7]  Bing-Zhong Wang,et al.  Novel Broadband Reflectarray Antenna with Windmill-Shaped Elements for Millimeter-Wave Application , 2007 .

[8]  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.

[9]  Marek E. Bialkowski,et al.  Phasing of a microstrip reflectarray using multi-dimensional scaling of its elements , 2008 .

[10]  M. R. Chaharmir,et al.  Broadband reflectarray antenna with double cross loops , 2006 .

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

[12]  Marek E. Bialkowski,et al.  A passive reflect array with dual‐feed microstrip patch elements , 1999 .

[13]  Marek E. Bialkowski,et al.  Investigations into unit cells offering an increased phasing range for single‐layer printed reflectarrays , 2008 .

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