Active antenna

About: Active antenna is a research topic. Over the lifetime, 2246 publications have been published within this topic receiving 26493 citations.

A self-steering planar array antenna for satellite broadcast reception

Abstract: The active planar array antenna offers a number of advantages, including use as a portable antenna for easy reception of direct Ku-band satellite television broadcasts. This paper presents a newly developed active planar array antenna which provides electronic beam-tracking without mechanical tracking equipment. The features of the antenna are: (1) use of a series-parallel fed microstrip array, (2) electromagnetically excited array by a coplanar patch connected to the coplanar waveguide, and (3) low noise down-converters and self-phasing units incorporated into the feed circuits for electronic beam-tracking. The paper discusses the design of the coplanar waveguide fed coplanar patch and the configuration of a self-phasing active planar array antenna. The measured gain of the experimental 9-element unit array antenna without active devices is 13.4 dBi at 11.85 GHz. Experimental results for a 216-element self-steering planar array of size 147/spl times/220.5 mm are also presented. >

Adaptive Interference Suppression of Phase-Only Thinned Arrays via Convex Optimization

Abstract: For antenna arrays, the conventional beamformer (CB) is perhaps the simplest kind of beamforming techniques with only phase shifters connected to the antenna elements. However, the output signal to interference and noise ratio (SINR) performance is usually quite away from the optimum. Besides, as the number of antenna elements increases, the hardware cost and power consumption are still too high for many applications. In this article, based on the phase-only CB, we propose different ways for thinning this kind of antenna arrays, which can be efficiently solved via common convex-optimization solvers. Specifically, the first-derived phase-only thinned array can largely increase the output SINR with fewer active antenna elements than the CB. The second one can keep the output SINR performance as that of the CB with a significantly smaller number of active antenna elements than that required by the CB. The third criterion is to add an additional constraint on the number of active antenna elements while maximizing the output SINR, which may benefit the hardware planning. Simulation results confirm the feasibilities of these methods, and the above-stated tasks are all fulfilled. Therefore, the proposed phase-only thinned arrays have the flexibility to provide various levels of array performance with reduced hardware resources.

PAPR-Limited Precoding in Massive MIMO Systems with Reflect- and Transmit-Array Antennas

Abstract: Conventional hybrid analog-digital architectures for millimeter-wave massive multiple-input multiple-output (MIMO) systems suffer from poor scalability and high implementational costs. The former is caused by the high power loss in the analog network, and the latter is due to the fact that classic MIMO transmission techniques require power amplifiers with high back-offs.This paper proposes a novel hybrid analog-digital architecture which addresses both of these challenges. This architecture implements the analog front-end via a passive reflect- or transmit-array to resolve the scalability issue. To keep the system cost-efficient, a digital precoder is designed whose peak-to-average power ratio (PAPR) on each active antenna is tunable. Using the approximate message passing algorithm, this precoder is implemented with tractable computational complexity. The proposed architecture allows for the use of power amplifiers with low back-offs which reduces the overall radio frequency cost of the system. Numerical results demonstrate that for low PAPRs, significant performance enhancements are achieved compared to the state of the art.

Integrated active antennas on silicon

Abstract: Integrated active antennas have been designed, fabricated, and used as low-cost front-ends for sensor and communication applications in the frequency bands around 61 and 76.5 GHz allocated for industrial and vehicular applications. The active antenna concept, i.e. the spatial integration of antenna and active element, results in minimization of the required chip size, high reproducibility, and, thus, low costs. The design of active millimeter wave antennas with respect to the impedance matching of antenna and active element as well as the radiation characteristics is discussed. The fabrication process on high resistivity silicon substrates is presented. Application of these front-ends in radar and communication systems is demonstrated.

Methods and devices for testing downlink and uplink wireless indexes of active antenna system

Abstract: The invention provides methods and devices for testing downlink and uplink wireless indexes of an active antenna system. The method for testing the downlink wireless index is carried out in a wave-absorbing dark room or a signal non-interference space and comprises the following steps of: acquiring calibration parameters of the wave-absorbing dark room or the signal non-interference space; configuring the active antenna system to transmit a wireless wave beam to a receiving antenna, wherein the wireless wave beam is triggered and generated by a base-band signal from a base-band processing unit outside the wave-absorbing dark room or the signal non-interference space, and then transmitted to a test instrument outside the wave-absorbing dark room or the signal non-interference space through the receiving antenna; and starting the base-band processing unit and the active antenna system, and testing the wireless indexes of the adjusted active antenna system according to the calibration parameters. By adoption of the technical scheme provided by the invention, testing of various wireless indexes of the active antenna system is realized.