New Retrodirective Antenna Techniques for Mobile Terminal Applications

This paper presents a new architecture together with practical results for a high performance analogue retrodirective array architecture with the following significant advantages: (1) It is able to constructively combine signals on receive, as well as on transmit, a feature not seen before on this type of array, (2) It is capable of operating with real life communication received signal levels as low as -120dBm. This work opens the way for fully co-operating Retrodirective arrays for use on un-stabilized co-operating mobile platforms where maximum S/N simultaneously on receive and on retransmit is automatically guaranteed.

Artificial Impedance Surfaces for Reduced Dispersion in Antenna Feeding Systems

An impedance surface is presented that reduces the dispersion experienced upon propagation of broadband pulses within rectangular waveguides. The surface impedance is selected so that, within a frequency range, the transverse resonance condition is satisfied for longitudinal wavenumber that varies linearly with frequency. A synthesis procedure for practical surface topologies consisting of periodic dipole arrays is described. An example involving a finite structure is employed to illustrate the reduced dispersion. Numerical simulation results obtained from in-house mode-matching method as well as HFSS are presented. A prototype is fabricated and tested experimentally validating the theoretical predictions.