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.

Dual-polarization performance of the phase-tilt antenna array in a casa dense network radar

Abstract: In this paper the evaluation of dual-polarized scanning performance of a large planar array antenna for a solid state radar for weather is discussed. The antenna array is designed to operate at 9.36 GHz ±50 MHz, and the transmission and reception mode is configured to work alternatively. The antenna array architecture based on a series-fed array configuration of Dual-Polarized Aperture Coupled Patch Antennas (DP-ACPA) was designed and implemented to achieve the required radar polarimetric performance at low cost. Measured patterns of the array in the elevation and azimuth plane are used to evaluate the two principal polarimetric radar parameters (Z dr and LDR) over the scanning range in azimuth plane. It is shown that the biases in the differential reflectivity due the cross-polarization of this antenna configuration are negligible in comparison with the biases produced for the mismatch antenna patterns (H and V).

Design of compact reconfigurable switched line microstrip phase shifters for phased array antenna

Abstract: Wireless communication systems are evolving toward multi-functionality. This multi functionality and reconfigurability provides users with options of connecting to different kinds of wireless services for many purposes at different times by providing additional degrees of freedom in the system e.g. cognitive radio, MIMO systems and high performance phased arrays. Although Phase shifters are important component in many RF microwave subsystems e.g. radar, phased array antennas, beam forming networks, frequency translators yet the reconfigurable phase shifter provides additional degree of freedom in these systems by reconfiguring the phase shift at a given frequency. In this paper design and simulation of reconfigurable switched line phase shifter for phased array antenna using Ansoft HFSS 14 is presented. The reconfigurability is achieved by loading phase shifter using high frequency PIN diodes which acts as microwave switches. A compact reconfigurable phase shifter has been designed which gives a very low insertion loss ≈ −1 dB and wide range of linear reconfigurable phase shift over frequency from 1 to 5 GHz. The designed phase shifter gives reconfigurable phase shift for different application i.e. at 1.8 GHz (GSM), 2.4GHz (Wi-Fi), 3GHz (traffic control and collision avoidance radars), 3.6GHz (WLAN) by appropriate settings of the 8 switch positions. As designed phase shifter can be used for 360° beam steering in phased array antenna.

Microstrip array antenna for automobile radar system

Abstract: Point to point communication brings a crucial responsibility to antennas since they are expected to provide a transmission between those devices. The Industry, Scientific and Medical (ISM) Band, Unlicensed with the range 2.4 - 2.4835 GHz is used as the operation band. In a high performance point to point application where size, weight, cost, performance, ease of installation are constrains, a suitable antenna is very much required. To meet these requirements, microstrip antenna is usually preferred. Microstrip antennas are currently one of the fastest growing segments in the telecommunications industry and promised to become the preferred medium of telecommunication in the future. Although microstrip antenna has several advantages, it also has several drawbacks such as low gain and narrow bandwidth. These disadvantages can be overcome by constructing many patch antennas in array configuration. This project focuses on the design of microstrip patch antenna with operating frequency at 2.45GHz for automobile radar system. The antenna is mainly intended to be used as receiving antenna and receives signals transmitted from an automobile radar system in order to control the movement of the car. An array design based on series fed configuration and consisting of four rectangular patch elements was designed, simulated, fabricated and measured. These elements are connected directly to the microstrip line at their corners and inclined 45 degree in order to achieve circular polarization. The simulation, fabrication and measurement methods were accomplished with the aid of MathCAD, AWR Microwave Office 2004, AutoCAD, FR4 Board, UV Equipment, Macroni Scalar Analyzer 6204 and Anechoic Chamber. The design met the ISM BAND Standard and able to operate in this Band. The fabricated array is found to have a variation in the operating frequency from the simulation resonant frequency. Return loss results of the fabricatd design have a value of -32.8dB with a bandwidth of 4.8%, which could be considered as a narrow band width. This further strengthens the theory of series feed configurations that arrays produce better return loss but narrower bandwidth than that of a single element.

Design considerations for antennas in UWB wireless communication systems

Abstract: General design considerations for the transmit/receive antennas in ultra-wideband wireless communication systems are discussed. The considerations include radiated power density lower than the required emission limits and maximum energy at the output of receive antennas. As an example, a pair of center-fed thin wire dipoles is investigated by using an FDTD method. The effects of the parameters of transmit/receive antennas and source pulses on the overall system performance are studied.

Adjustable-tilt antenna

Abstract: The present invention lies in the field of antennas for land cellular radio communications networks, and it relates to a remote control method for adjusting the tilt of the radiation pattern relative to the horizontal of the antennas of a base station. The invention also relates to an antenna fitted with means for adjusting its tilt and to a system for remote control of the tilt. The technical field of the invention is active antennas (also known as “smart” antennas or as “adaptive” antennas) for networks for communicating with mobile telecommunications terminals. According to the invention, an antenna for a land cellular telecommunications network, the antenna comprises radiating elements and feeder means for feeding said radiating elements with radio frequency signals; said feeder means include electronic phase shifter means for obtaining phase shifts between said signals so as to enable the tilt of the radiation pattern in a vertical plane to be adjusted remotely.