Decoupling Efficiency of a Wideband Vivaldi Focal Plane Array Feeding a Reflector Antenna

A focal plane array (FPA) feeding a reflector can be used to achieve a large field of view (FOV) with overlapping simultaneous beams. In order to provide a continuous FOV over more than an octave bandwidth, the inter-element spacing in the FPA has to be electrically small over large parts of the band. This will inevitably result in strong mutual coupling effects between the array elements. On transmit, the total lost power due to mutual coupling can be quantified by the decoupling efficiency, a term recently introduced for antenna arrays. This paper presents measured decoupling efficiencies of a Vivaldi element FPA operating between 2.3 and 7 GHz. The radiation patterns of the FPA are calculated for two beam excitations by using measured embedded element patterns, and the corresponding decoupling efficiencies are evaluated by using measured S -parameters between all element ports. The FPA is assumed to illuminate a deep reflector with F/D=0.35 , and the overall reflector aperture efficiencies are computed. The decoupling efficiencies are also determined through the measurements of the total radiation efficiencies in a reverberation chamber, which includes material absorption losses.

[1]  Per-Simon Kildal,et al.  Scalar horn with shaped lens improves Cassegrain efficiency , 1984 .

[2]  Marianna Ivashina,et al.  Definition of unifying decoupling efficiency of different array antennas—Case study of dense focal plane array feed for parabolic reflector , 2010 .

[3]  A. Ardenne.  Design considerations for a multibeam receiver for millimeter wave astronomy , 1987 .

[5]  M. Ivashina,et al.  A way to improve the field of view of the radiotelescope with a dense focal plane array , 2002, 12th International Conference Microwave and Telecommunication Technology.

[6]  B.MacA. Thomas,et al.  Fields in the image space of symmetrical focusing reflectors. , 1968 .

[7]  D. Schaubert,et al.  Elimination of impedance anomalies in single- and dual-polarized endfire tapered slot phased arrays , 2000 .

[8]  A. Mrstik,et al.  Scan limits of off-axis fed parabolic reflectors , 1979 .

[9]  Tan-Huat Chio,et al.  Experimental results of 144-element dual-polarized endfire tapered-slot phased arrays , 2000 .

[10]  Per-Simon Kildal,et al.  Analysis of numerically specified multireflector antennas by kinematic and dynamic ray tracing , 1990 .

[11]  Per-Simon Kildal,et al.  Correlation and capacity of MIMO systems and mutual coupling, radiation efficiency, and diversity gain of their antennas: simulations and measurements in a reverberation chamber , 2004, IEEE Communications Magazine.

[12]  M. Jensen,et al.  Effects of mutual coupling on interference mitigation with a focal plane array , 2005, IEEE Transactions on Antennas and Propagation.

[13]  B. Veidt.  Memo 71 Focal-Plane Array Architectures : Horn Clusters vs . Phased-Array Techniques , 2006 .

[14]  J. Richard Fisher,et al.  Full-sampling array feeds for radio telescopes , 2000, Astronomical Telescopes and Instrumentation.

[15]  W.K. Kahn.  Element Efficiency: A Unifying Concept for Array Antennas , 2007, IEEE Antennas and Propagation Magazine.

[16]  Y. Rahmat-Samii.  Array feeds for reflector surface distortion compensation: concepts and implementation , 1990, IEEE Antennas and Propagation Magazine.

[17]  P.-S. Kildal,et al.  Designing reverberation chambers for measurements of small antennas and wireless terminals: Accuracy, frequency resolution, lowest frequency of operation, loading and shielding of chamber , 2006, 2006 First European Conference on Antennas and Propagation.

[18]  E. Woestenburg,et al.  Multifrequency Cryogenically Cooled Front-End Receivers for the Westerbork Synthesis Radio Telescope , 1982 .

[19]  Raj Mittra,et al.  A New Direction in Computational Electromagnetics: Solving Large Problems Using the Parallel FDTD on the BlueGene/L Supercomputer Providing Teraflop-Level Performance , 2008, IEEE Antennas and Propagation Magazine.

[20]  P. Hall,et al.  Encircled power study of focal plane field for estimating focal plane array size , 2005, 2005 IEEE Antennas and Propagation Society International Symposium.

[21]  Marianna Ivashina,et al.  Optimal Number of Elements and Element Spacing of Wide-Band Focal Plane Arrays for a New Generation Radio Telescope , 2007 .

[22]  W. Kahn,et al.  Ideal efficiency of a radiating element in an infinite array , 1967 .

[23]  Marianna Ivashina,et al.  Decoupling Efficiency of a Wideband Vivaldi Focal Plane Array Feeding a Reflector Antenna , 2009 .

[24]  P. Smith,et al.  Scanning capabilities of large parabolic cylinder reflector antennas with phased-array feeds , 1981 .

[25]  Li Li,et al.  Experimental results for a focal plane array, synthesized with conjugate field method , 2004, IEEE Antennas and Propagation Society Symposium, 2004..