Title :
Ultra-Wideband, True-Time-Delay Reflectarray Antennas Using Ground-Plane-Backed, Miniaturized-Element Frequency Selective Surfaces
Author :
Hasan Abadi, Seyed Mohamad Amin Momeni ; Ghaemi, Kasra ; Behdad, Nader
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Wisconsin-Madison, Madison, WI, USA
Abstract :
We introduce a new method for designing low-profile reflectarray antennas with broadband, true-time-delay (TTD) responses. Such structures are composed of numerous reflective spatial time-delay units distributed over a planar surface. Each spatial time-delay unit is a unit cell of a ground-plane-backed miniaturized-element frequency selective surface (MEFSS) composed of nonresonant elements. Each element is a lowpass type MEFSS composed of a stack of nonresonant patches separated from one another by thin dielectric substrates, and the whole structure is backed with a ground plane. A prototype of the proposed MEFSS-based TTD reflectarray with the focal length to aperture diameter ratio (f/D) of 0.87 operating at the center frequency of 10 GHz is designed, fabricated, and experimentally characterized both in time and frequency domains. It is demonstrated that the fabricated TTD reflectarray operates over a bandwidth of 40% without any significant chromatic aberrations. The proposed antenna provides a realized gain of 23 dB when fed with an X-band horn antenna and shows a gain variation of about 4 dB in the 8-12 GHz range. The antenna also shows consistent radiation characteristics and relatively low side-lobe levels across its entire band of operation.
Keywords :
aberrations; antenna radiation patterns; delays; dielectric thin films; frequency selective surfaces; horn antennas; reflectarray antennas; time-frequency analysis; ultra wideband antennas; X-band horn antenna; antenna radiation characteristics; chromatic aberrations; frequency 10 GHz; frequency 8 GHz to 12 GHz; frequency domain analysis; gain 23 dB; gain variation; ground plane backed miniaturized element frequency selective surface; low-pass type MEFSS-based TTD reflectarray; nonresonant elements; nonresonant patch; planar surface; reflective spatial time delay unit cell; side lobe level; thin dielectric substrate; time domain analysis; true time delay reflectarray antenna; ultra wideband antenna; Antenna feeds; Apertures; Broadband antennas; Delay effects; Delays; Antenna arrays; frequency selective surfaces; periodic structures; reflectarrays; time-delay arrays;
Journal_Title :
Antennas and Propagation, IEEE Transactions on
DOI :
10.1109/TAP.2014.2381231