Active antenna

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

Ka-band Fresnel lens antenna fed with an active linear microstrip patch array

Abstract: The design of a linear microstrip array and Fresnel lens combination as a potential candidate for Ka-band satellite communications is presented. Medium-power amplifiers are distributed within the array to achieve a high EIRP required for satellite communications. This architecture may be used as an alternative to the conventional horn-fed reflector antenna with a single high-power amplifier.

Method to improve active antenna system performance in the presence of mutual coupling

Abstract: A method in a network node comprises receiving a first input signal from a baseband processing unit of a first antenna branch, receiving a second input signal from a baseband processing unit of a second antenna branch, determining a first and second compensation coefficient, applying the first compensation coefficient to the second input signal to generate a first output signal, applying the second compensation coefficient to the first input signal to generate a second output signal, outputting the first output signal to a first power amplifier of the first antenna branch, the first output signal compensating for a mutual coupling from the second antenna branch to the first antenna branch, and outputting the second output signal to a second power amplifier of the second antenna branch, the second output signal compensating for a mutual coupling from the first antenna branch to the second antenna branch.

Code Index Modulation and Spatial Modulation: A New High Rate and Energy Efficient Scheme for MIMO Systems

Abstract: In this paper, in order to increase data rate, error performance and energy efficiency in wireless communication systems, a new multiple-input multiple-output (MIMO) transmission scheme, called code index modulation and spatial modulation (CIM-SM), is proposed over the Nakagami-m fading channel by combining recently two promising modulation techniques, SM and CIM. In the CIM-SM scheme, incoming data bits specify activated transmit antenna indices, two modulated symbols as well as their corresponding spreading code indices. Therefore, the information bits are conveyed not only by the two modulated symbols but also by the active antenna indices of SM as well as the spreading code indices. Consequently, the proposed CIM-SM scheme spends less transmission power while performing faster data transmission compared with the conventional direct sequence spread spectrum (DS-SS), SM and CIM-SS systems. Our computer simulations show that CIM-SM scheme provides considerably better error performance than DS-SS, SM and CIM-SS systems. In addition, the performance analysis of the proposed system is performed over the Nakagami-m fading channels for BPSK modulation.

Series-connected couplers for active antenna systems

Abstract: In one embodiment, an antenna system has a plurality of antenna paths and a calibration circuit. Each of the antenna paths has a transceiver and an antenna element. The calibration circuit has (i) a calibration transceiver and a different coupler coupled to each antenna path. The couplers are connected in series with one another and with the calibration transceiver. Connecting the couplers in series, rather than in parallel, reduces the amount of cabling needed and the need for a combiner/splitter or switch matrix between the couplers and the calibration transceiver, thereby reducing the cost, volume, and/or weight associated with the calibration circuit.

Scanning, circularly polarized varied impedance transmission line antenna

Abstract: The present invention features a cross-element, steerable, scanning meander line loaded (MLA) antenna with circular polarization. The transmission lines comprise a plurality of alternating or stepped impedance sections with the high impedance elements acting as active antenna elements. The impedance varies depending upon the spacing from the moveable ground plane. The orthogonal MLA elements allow the application of an in-phase and a 90° shifted signal, thus each linear array radiates a circularly polarized RF signal. Controlling the spacing between the ground plane and transmission line provides relative phase control between the active elements and thereby phased-array directional control of the antenna. Forming a two-dimensional array of these linear arrays, produces a compact, low-cost, scanning, phased-array antenna.