A dual polarization, broadband, millimeter‐wave reflectarray using modified cross loop element

Abstract

A Ka‐band reflectarray consisting of modified cross loop is investigated in this article for millimeter‐wave broadband dual‐polarization applications. It consists of 40 × 40 unit cells that covered an area of 200 × 200 mm2 and a multimode conical horn antenna which is connected to an orthomode transducer as the offset feed. Its unit cell is composed of a solid cross inside and a cross loop outside, which can lead to nearly 550° linear phase shift curve by varying its length. After this proposed structure has been analyzed and compared with the traditional wideband element (i.e., double cross loop), it is used in the reflectarray. An equivalent circuit model with an insightful field distribution is used to analyze their different behaviors when it resonated at the same operating frequency. For vertical and horizontal polarization modes, the peak gain are measured to be 34.3 and 33.5 dB, the aperture efficiency are 48.6% and 40.4% at the center frequency of 32 GHz, respectively. The 1.5 dB gain bandwidth are close to 18% and 15%, which is better than conventional millimeter‐wave single‐layer ones. This new reflectarray antenna is especially useful for millimeter‐wave broadband dual‐polarization applications. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:287–293, 2014

Broadband Low-Cost Reflectarray Using Modified Double-Square Loop Loaded by Spiral Stubs

“…Elements with a linear-phase response are usually employed to improve the bandwidth [3]. The phase response linearization can be obtained by the use of thicker substrates, stacked patches, multi-resonance units [4], phase-delay lines [5], and sub-wavelength coupled-resonant elements [6]. Using multi-resonance structure in sub-wavelength lattice is the most absorbing approach among them.…”

A low‐cost variable polarization reflectarray based on controllable wave‐path difference

“…The feeder is located at (0, −70.98 mm, 195 mm) with the incident angle θ i = 20° and the polarization title angle γ = 45° ( φ f = 135°). All the configuration parameters are calculated through the process discussed in References .…”

Design and evaluation of a wideband reflectarray antenna using cross dipole with double‐ring elements

“…In small‐ and medium‐sized reflectarray antennas, this is attributed to the narrow bandwidth and dynamic phase range of the reflecting elements . Since the radiation performance of the reflectarray antenna primarily depends on that of the reflecting elements, several researchers have directed efforts at improving the bandwidth and radiation performance of the elements . Some of the techniques adopted to enhance the bandwidth are (a) the use of a thick substrate or foam loading, (b) multi‐resonant elements design, and (c) multilayer configuration .…”

“…It appears that a combination of the first two methods are more commonly investigated than the third one, as it introduces additional design complexity and large substrate losses . Among the several element designs reported to enhance the bandwidth, simple, cross‐dipole based elements have been popularly used for bandwidth enhancement of reflectarray antennas . Such specific configurations include multi‐cross loops, cross loop and square ring slots loaded patch, double cross loops, and modified cross loop element .…”