Active antenna

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

Apparatus and method for an active antenna system with near-field radio frequency probes

Abstract: Field-serviceable radio frequency modules can be achieved by replacing hard-wired radio frequency (RF) feedback paths with external near-field RF probes. Notably, the near-field RF probes may allow for the RF module to be installed/re-installed on a backplane or other support structure without fowling factory calibration settings. Multiple near-field RF probes can monitor a single RF module. Additionally, a single near-field RF probe can monitor multiple RF modules.

Active Antenna Tracking System with Directional Antennas for Enhancing Wireless Communication Capabilities of a Networked Robotic System

Abstract: This paper presents a networked robotic system design capable of enhancing wireless communication capabilities communication range and bandwidth. The core of the system is active antenna tracking with directional antennas. The proposed system is decentralized and consists mainly of a mobile robot system and a command center system. Each system is equipped with off-the-shelf network devices such as antennas, access points AP, and network switches. For directional antennas to be beneficial to our system, we propose a weighted centroid algorithm WCA to provide active antenna tracking and direction-of-arrival DOA estimation. This system can be used in GPS-denied environments as our system does not require the aid of additional sensors to provide location information. Through extensive field experiments in different environments, including a fire training center and with various antenna selections, such as omni-to-omni, omni-to-directional, and directional-to-directional antennas, we demonstrate the effectiveness of our proposed system. We expect that our system can be applied in a variety of rescue, surveillance, and emergency scenarios where high bandwidth and long-distance communications are needed.

Vision based active antenna

Abstract: This paper proposes the vision based active antenna (VBAA) that can detect the contact force, the stiffness of the environment, and the contact location between an insensitive elastic antenna and an environment, through the observation of the antenna's shape by a camera. We show that both the contact location and the contact force can be estimated by measuring two arbitrary points on the antenna after a pushing motion; even though the exact contact point is hidden by occlusion. By considering the geometrical relationship between. The virtual (without environment) and the real (with environment) displacements of the contact point, the stiffness of the environment can also be estimated, which our conventional active antenna can not do. We present the basic working principle of the VBAA and give experimental verification.

Generalized spatial modulation with transmit antenna grouping for correlated channels

Abstract: In this paper, an effective generalized spatial modulation (GenSM) scheme with transmit antenna grouping is proposed to overcome the performance degradation caused by correlated channels. In the proposed scheme, the transmit antennas are divided into several equal-sized groups, and spatial modulation (SM) is carried out to select one active antenna in each group independently. It is quite different from the conventional GenSM which jointly selects active antenna set. Apart from the straightforward block grouping method, which collects the adjacent antennas to the same group, interleaved grouping is also introduced. It can maximize the average distance between the antennas in the same group, since the channel correlation depends on it. To evaluate the performance, a closed-form expression of the average bit error probability (ABEP) upper bound is derived for all proposed grouping methods and Monte-Carlo simulations are conducted to verify the analysis and reveal the performance gain of the proposed scheme in terms of bit error rate (BER) in comparison with conventional GenSM and SM.

Antenna system optimized for siso and mimo operation

Abstract: An active antenna system and algorithm is described that provides for improved performance from LTE communication systems operating in Category 1 mode, where one antenna is used. For the LTE SISO case (category 1), a modal antenna capable of generating multiple radiation patterns will provide improved throughput due to improved resistance to fading. Modal (Null Steering) antenna technology is implemented in a multi-antenna system to provide for single and multiple antenna operation wherein one or more antennas have two or more radiation modes. An algorithm has been developed that determines when to switch from SISO to MIMO operation.