Topic
Reflective array antenna
About: Reflective array antenna is a research topic. Over the lifetime, 4366 publications have been published within this topic receiving 57884 citations.
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TL;DR: In this paper, a phase shifter was used to tune the bias magnetic field of the antenna elements, resulting in steering of the radiation beam in a one-dimensional space. But the performance of the system was limited.
Abstract: A phased array antenna containing four linear microstrip patch elements has been fabricated and tested. The elements were fed through single-crystal yttrium-iron-garnet (YIG) phase shifters. By varying the bias magnetic field, the input phases to the antenna elements can thus been tuned, resulting in steering of the radiation beam in one dimension. Measurements compared reasonably well with calculations.
19 citations
Patent•
08 Nov 2013
TL;DR: In this paper, a reflective array surface was proposed for a phase-shifting effect on an incident electromagnetic wave and a reflection layer that is disposed on one side of the functional board and is configured to reflect an electromagnetic wave.
Abstract: The present invention provides a reflective array surface. The reflective array surface includes a functional board that is configured to perform beam modulation on an incident electromagnetic wave and a reflection layer that is disposed on one side of the functional board and is configured to reflect an electromagnetic wave, where the functional board includes two or more functional board units and the reflection layer includes reflection units, where the number of reflection units corresponds to the number of functional board units, where the functional board unit and a reflection unit corresponding to the functional board constitute a phase-shifting unit that is used for phase shifting. According to the reflective array surface in the present invention, a functional board unit and a reflection unit corresponding to the functional board unit constitute a phase-shifting unit that is used for phase shifting, which can solve a problem in the prior art that a phase-shifting effect is not exquisite enough and a beam modulation capability for an electromagnetic wave is poor, thereby affecting bandwidth and working performance of a reflective array antenna. In addition, the present invention further provides a reflective array antenna.
19 citations
TL;DR: In this article, the problem of beam squinting in circularly polarized offset reflector antennas is solved by using a novel focal plane array concept that consists of sequentially rotated linearly polarized elements.
Abstract: The problem of beam squinting in circularly polarized offset reflector antennas is solved by using a novel focal-plane array concept that consists of sequentially rotated linearly polarized elements. This concept can be used to facilitate beam steering in full-duplex communication with satellite Internet (VSAT) operating in the Ka-band. A prototype consisting of a 75-cm offset dish illuminated by a $2 \times 2$ array of sequentially rotated aperture-coupled microstrip antennas was developed and tested at 20 GHz. Experimental results clearly demonstrate the removal of the beam-squint and resulted in an axial ratio (AR) below 1 dB within the 1-dB beamwidth of the main beam.
19 citations
01 Jan 2014
TL;DR: In this article, the authors studied two very practical traveling wave antennas: helical and Yagi-Uda, and reviewed the basic theories of these two antennas, and several design examples will be presented.
Abstract: Conventional center-fed linear wire or cylindrical type antennas were studied in the previous chapters. These types of configurations have an almost sinusoidal current amplitude distribution, with an approximately constant phase distribution. However, as the length of the wire increases beyond the conventional λ/2 dipole, the sinusoidal current distribution becomes a standing wave as a result of the reflection at the open end of the wire. This chapter will study two very practical traveling wave antennas: helical and Yagi-Uda. The helical antenna is a very good example of a traveling wave antenna that exhibits excellent radiation characteristics. It consists of a single or multiple conductors that are wound into a helical shape. It has broadband characteristics and also can provide circular polarization, which is a desired feature for many applications. The Yagi-Uda antenna consists of a linear array of elements with only one of the elements energized. The other elements in the array act as parasitic elements, and their currents are induced by mutual coupling. This chapter will review the basic theories of these two antennas, and several design examples will be presented.
19 citations
TL;DR: The effect of mutual coupling on a space diversity combined signal from an optimum resistive load network lessens when the antenna spacing d and the number of elements M increase, and the cumulative distribution curves of an M -branch signal with mutual effects included show only a small difference compared to an array with no coupling.
Abstract: The effect of mutual coupling on a space diversity combined signal from an optimum resistive load network lessens when the antenna spacing d and the number of elements M increase. When d is greater than 0.2λ, the cumulative distribution curves of an M -branch signal with mutual effects included show only a small difference compared to an array with no coupling, and are close to the cumulative distribution curve of an array with M independent branches. For the average SNR of an array with 100 branches obtained from an optimum resistive load network to be within -3 dB of the SNR from independent branches the required antenna spacing is at least 0.25λ, for an in-line array and 0.5λ, for a planar array. Since a planar array is much smaller than an in-line array for equal performance, the planar array is a more desirable configuration.
19 citations