Active antenna

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

A Novel Method for Calibrating Deployed Active Antenna Arrays

Abstract: This study proposes a simple self-calibration system that involves applying the phase-match method (PMM) in the far-field calibration of a deployed active array. When the proposed self-calibration approach is employed, an antenna array system can be maintained at a ground-based station, and no expensive and complex test equipment is required. An EM-based simulation method was applied to validate the proposed method numerically. Finally, an eight-element microstrip array operating at 3.6 GHz was designed to study the proposed method experimentally. The measured results validated the effectiveness of the proposed method in calibrating deployed antenna array systems.

Miniaturized Self-Oscillating Annular Ring Active Integrated Antennas

Abstract: With a direct integration of a field effect transistor (FET) into a C-shaped ring radiator, a novel miniaturized self-oscillating annular ring active integrated antenna is proposed and investigated in this paper. The direct integration approach provides a solid basis for the miniaturization while the slow-wave loading effect from the unstable transistor further enhances the reduction ratio. It makes the proposed design show an extraordinarily compact size of 0.041λg2 , which is 40% the size of the second smallest one in literature using printed circuit board technology. The proposed active antenna, providing overall comparable performance to the previous designs, has an EIRP of 7.30 dBm, DC-to-RF efficiency of 25.9%, phase noise of -91.9 dBc/Hz@100 kHz offset, and an oscillator FOM of -168.76 dBc/Hz. By introducing a reverse-biased varactor diode, this miniaturized active antenna also demonstrates promising voltage controllability with a high VCO gain of 48.7 MHz/V. The antenna geometry and modeling, design concept, simulation scheme, and experimental results are discussed thoroughly in this paper.

Active antenna array having analogue transmitter linearisation and a method for predistortion of radio signals

Abstract: An active antenna array for a mobile communications network comprising: a digital signal processor connected to a plurality of digital-to-analogue conversion blocks; a plurality of antenna elements; a plurality of transmission paths, whereby an individual one of the plurality of transmission paths is connected between an individual one of the digital-to-analogue conversion blocks and an individual one of the plurality of antenna elements, whereby an individual one of the plurality of transmission paths comprises a predistorter and a coupler; a plurality of paths connected between an individual one of the couplers and a single combiner; a single feedback path connected between the single combiner and a predistorter coefficient calculation unit; and a coefficient update path connected between the predistorter coefficient calculation unit and at least an individual one of the predistorters. A method for predistortion of radio signals is also disclosed.

Small-Size X-Band Active Integrated Antenna With Feedback Loop

Abstract: A small-sized active integrated antenna (AIA), consisting of a transmission feedback oscillator loaded with a microstrip antenna is presented in this paper. The oscillator antenna, which consists of a NEC super low noise high frequency field effect transistor (HF FET) integrated into the center of a segmented patch antenna, was designed for X-band at 8.50 GHz, and occupies a 5 times 6 mm2 area. The active integrated antenna demonstrates stable oscillations and excellent radiation patterns at X-band design frequencies. When biased using a single 1.5 volt battery connected between the source and drain and with the gate terminal open, the antenna effective isotropic radiated power (EIRP) and direct current (DC)-to-radiated radio frequency (RF) conversion efficiency are +11.2 dBm and 10.5%, respectively. The radiated power level and directivity are +4.5 dBm and 6.7 dBi, respectively. The phase noise at 100 kHz offset from the carrier is -87.5 dBc/Hz, which is a notable improvement over existing AIA designs. The AIA features compact size and simple geometry, yet provides radiated power levels and radiation efficiencies that are comparable to values typically obtained using circuits that occupy larger areas, and use thicker substrates with much lower dielectric constant values.

Antenna array and method for operating antenna array

Abstract: The present invention refers to an active antenna array having a plurality of antenna elements comprising: at least one first subset of the plurality of antenna elements, the at least one first subset relaying a first radio signal having a first antenna beam pattern; and at least one second subset of the plurality of antenna elements, the at least one second subset relaying a second radio signal having a second antenna beam pattern, wherein at least one of the plurality of antenna elements is a common antenna element belonging to both the first subset and the second subset. A method for operating the active antenna array is also disclosed.