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.

Broadband near-field filters for Simultaneous Transmit and Receive in a small two-dimensional array

Abstract: In order to enable Simultaneous Transmit and Receive (STAR), it is essential to provide high isolation between antenna elements. A novel technique is presented here in which tunable resonators are used in the near-field of an array of antennas to provide transmission zeros in the coupling between antennas. By using two sets of tunable resonators between each set of adjacent antennas, it is possible to significantly increase the bandwidth of the isolation provided relative to previous topologies used to give isolation between planar antennas.

Body wearable antennas for UHF/VHF

Abstract: The development of antennas which can be worn on the body is of increasing interest within both the military and civil domain. Body wearable antennas present a considerable design challenge, particularly as most applications require the antenna to be unobtrusive and low-profile. The majority of recent work has concentrated on antennas for WLAN or UWB frequencies. At these frequencies the antennas are relatively small and can be made low-profile to fit on the body. It is also possible to incorporate a ground-plane (such as a PIFA or patch antenna) which significantly reduces the effect of the body on antenna performance. In this paper, antennas which operate across the 100-500 MHz band are considered. At these lower frequencies the antennas are physically larger and cannot incorporate an effective ground-plane so the effect of the body is significant. In this work it was assumed simultaneous coverage of the entire band and omnidirectional radiation patterns were required. This paper discusses the antennas considered, and those selected to meet these challenging requirements. Design of the antennas using computational electromagnetics software is presented. The development of prototype antennas is also presented, along with results of antenna pattern measurements.

Frequency-hopping array antenna system

Abstract: A phased-array antenna (18) for use with a frequency-hopping transmitter (16) includes a plurality of elemental antennas (210), each associated with a phase-shifter (212) which is controlled (20) to form a beam (216) in the desired direction at a base frequency. The antenna elements (210, 212) are formed into subarrays (408t, 408b) each of which is fed from a common port (310). A further phase-shifter (312) is associated with each subarray, for imposing a phase shift on a group of elements of the overall array. The further phase-shifters are controlled when the frequency of the transmitter is away from the base frequency, to cause a stepwise-continuous correction phase across the array, which maintains the desired beam direction.

Dual-band microstrip antenna array

Abstract: A dual-band antenna array (50) for use in a base station for mobile telephone communications consists of a first linear array of microstrip or patch antennas (52) for use over the GSM band and a second linear array of crossed dipoles (56) for use over the PCN band. The PCN antennas are at half the spacings of the GSM antennas. Alternate ones of the PCN crossed dipole antennas are located above respective GSM patch antennas, and a conductive plate or sheet (66) between them functions both as a parasitic element for the microstrip antenna and as a reflector for the crossed dipole antenna.

Phased array antennas with binary phase shifters

Abstract: Steerable phased array antennas of the tapered type in which the antenna ment power is maximum at the center of the array and tapers off on either side thereof. The phase shifters of each antenna element are of the binary digital type with the number of stages and hence the phase accuracy being maximum for the high power center antenna elements and tapering off on either side thereof. Redundant stages for the binary phase shifters can be provided to increase reliability.