Active antenna

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

Coexistence Evaluation of LTE with Active Antenna System

Abstract: Due to the new radio architecture of Active Antenna System (AAS), the LTE BS equipped with AAS will have more flexible RF planning than that equipped with passive antenna. However, the new RF characteristic of AAS will have potential impacts on the existing BS RF requirements, which is imperative to be evaluated. In this paper, general antenna pattern and spatial Adjacent Channel Leakage Ratio (ACLR) are introduced considering the new RF features of AAS, and the impacts of AAS on BS performance are analyzed based on the AAS fundamental applications. System-level coexistence simulation is conducted to evaluate the RF features of transmitter and receiver of AAS on BS performance. Simulation results show that RF feature of spatial ACLR of AAS transmitter has little impact on throughput loss in victim system and ACLR of 45 dB per transmitter of AAS can fully meet the coexistence requirement; RF feature of in-band blocking level of individual receiver of AAS is higher than that of receiver of BS equipped with passive antenna around 1-4 dB, which imposes harder requirement to design the channel selection filter in the individual receiver of AAS, thus in-band blocking requirement needs to be redefined for AAS BS in the existing 3GPP specification.

Mock up definition and test plan for a two-phase mechanically pumped loop (2 ΦMPDL) to manage the thermal dissipation of an active antenna

Abstract: To face the thermal control challenges of future po werful telecommunication satellites, THALES ALENIA SPACE (TAS), is currently developing a two-phase mechanically pumped loop (2 ΦMPDL) to transport the heat dissipation from an active antenna (up to 4kW) to d edicated large deployable radiators. After remaining shortly the thermal control design of the Active Antenna [8], this paper gives firstly an overview of mock up definition. The mock up has been designed in such a way to be representative in term of mass, power dissipation and thermal interfaces. The main part o f the existing 6kW prototype (radiator, heat contro l accumulator, cooling system) is reused while the specific part ( payload mock up) is manufactured. In a second part, the test plan and test sequence will be presented. The aim is to characterise the thermal performance of the thermal control for the sizing cases and to demonstrate the good behaviour for severe transient. The operational mode of the a ctive antenna drives the cases which will be tested in steady sta te and transient.

Flight data assisted active antenna system for air-to-ground applications

Abstract: Methods and apparatuses for controlling radio resources of radio units in air-to-ground mobile communications systems that include at least an aircraft carrying a transceiver station and a ground basestation, apt to communicate with each other. The radio units are provided with beamforming and/or massive MIMO antenna systems, and are controlled by the apparatuses using control data. The apparatuses are configured to receive flight data related to the aircraft, estimate a timed trajectory and a required data rate, as a function of the flight data. Then the apparatuses determine a sequence of control data for said antenna systems to form radio beams and/or connectivity spots directed towards said transceiver station, respectively to the ground basestation, while the allocated data rate is at least equal to the required data rate.The sequence of control data is then provided to respective antenna systems.

Reader-writer active antenna slave mode transmitting and receiving circuit

Abstract: The invention discloses a reader-writer active antenna slave mode transmitting and receiving circuit. The reader-writer active antenna slave mode transmitting and receiving circuit includes a mfin (Mifare In) Miller pulse filtering transmitting circuit, a mfin Miller pulse detection circuit, a state machine conversion and output control signal circuit, a decoding clock synchronous circuit, and a mfout (Mifare out) Manchester code output circuit, wherein mfin and mfout pins of the reader-writer are utilized to enable the reader-writer in the main mode to use the mfout to transmit a TYPEA 106K Miller pulse in an ISO14443 protocol and enable the reader-writer in the slave mode to receive the TYPEA 106K Miller pulse in the ISO14443 protocol and perform digital filtering and send the Miller pulse to a TX interface to realize transmission of an RF signal and detect whether the Miller pulse is transmitted; according to the jumping of the state machine, switching of the reception state from the transmission state of the reader-writer in the slave mode is realized so as to prepare for receiving the data returned from a card; and digital decoding is performed by means of the signal of analog reception demodulation which directly utilizes the mfout to return the data to the mfin in the main mode so as to realize application of the active antenna which is interacted between the reader-writer and the card.

Active Antennas for Commercial and Military Communications Satellites - A Review

Abstract: Active antennas have been in use in communications satellites for decades. The antenna configurations include array-fed reflectors, multiple-beam lenses and direct radiating phased arrays. The active feedings of the antennas include single amplifier per radiating element and matrix power amplifiers shared between clusters of radiating elements. This paper reviews the combinations of antenna configurations and active feedings as applied to different satellite systems. The miniaturization of active and beam forming components using MMIC technology are also addressed. The examples presented in this paper scan four decades of development at all frequency bands from L- to Ka-bands. The applications cover commercial and military systems with multiple spot beams, cellular mobile systems, broadband systems and dynamic high-power high-capacity systems. 1. Introduction Present and future communications satellites for both commercial and military applications require considerable flexibility in order to use the limited power and bandwidth resources efficiently. Broadband applications are among the services that are envisioned for future satellite systems and flexibility is also required for such applications. Flexibilities include forming multiple beams, sharing power between beams, rapidly reconfiguring and re-pointing the beams, high reliability and compensation for component failures. These requirements make active antennas with distributed and shared power amplifiers the preferred choice over conventional passive antennas with separate amplifiers per transponder or separate amplifiers per beam. Advances in monolithic microwave integrated circuits (MMIC) and other miniaturization technologies allowed the realization of lightweight, power efficient and flexible active antennas for satellite applications. The active antenna can be either a direct radiating phased array, a phased array feeding a reflector or lens system, or a matrix-amplifier-fed reflector or lens antenna. The direct radiating phased array may be a potential candidate when the required apertures are not prohibitive. Appropriate dual reflector and lens optic designs can be considered for providing array magnification when the array size may encounter packaging difficulties. A smaller size array may be used in conjunction with lens or unfurlable reflector systems to produce a potentially lightweight antenna with performance equivalent to that of a direct radiating array. A number of successful designs for active arrays found their ways into commercial and military satellite systems, and more are being considered for future satellites. The following sections review some of those designs. 2. Matrix Amplifiers in AMSC, Inmarsat-3, ETS-VI and ARTEMIS Satellites Among the commercial satellites that use power sharing between the beams through matrix amplifiers are Inmarsat-3, AMSC, ARTEMIS at L-band and ETS-VI at S-band (1). Inmarsat-3 generates 7 spot beams using a 22-element cup helix feed array and 22 SSPAs distributed among four 4X4 matrices and one 6X6 matrix. The total power of the each individual matrix is routed to any combination of the beams. AMSC (or MSAT) uses two matrix power amplifiers to feed 6 beams independently. Each of the two matrices has the flexibility of directing all of its RF power into a single beam, while at the same time loading each of the SSPAs equally to minimize intermodulation noise. ETS-VI uses a similar concept, while in ARTEMIS the shared amplifiers are sandwiched between a beam forming network and a Butler matrix.