Topic
Active antenna
About: Active antenna is a research topic. Over the lifetime, 2246 publications have been published within this topic receiving 26493 citations.
Papers published on a yearly basis
Papers
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TL;DR: In this article, a piecewise closed-loop (PW) DPD solution and low-complexity gradient-adaptive parameter learning algorithms, together with a region partitioning method, are proposed for digital predistortion (DPD)-based linearization of strongly nonlinear mm-wave active antenna arrays.
Abstract: In this article, we describe a novel framework for digital predistortion (DPD)-based linearization of strongly nonlinear millimeter-wave active antenna arrays. Specifically, we formulate a piecewise (PW) closed-loop (CL) DPD solution and low-complexity gradient-adaptive parameter learning algorithms, together with a region partitioning method, which can efficiently handle deep compression of the PA units. The impact of beamsteering on the DPD performance is studied, showing strong beam-dependence, thus necessitating frequent updating of the DPD. In order to facilitate fast adaptation, an inexpensive, noniterative, pruning algorithm is introduced, which allows us to significantly reduce the number of model coefficients. The proposed methods are validated with extensive over-the-air RF measurements on a 64-element active antenna array transmitter operating at 28-GHz carrier frequency and transmitting a 400-MHz 5G new radio (NR) standard-compliant orthogonal frequency-division multiplexing waveform. The obtained results demonstrate the excellent linearization capabilities of the proposed solution, conforming to the new 5G NR requirements for frequency range 2 (FR2) in terms of both in-band waveform quality and out-of-band emissions. The proposed PW-CL DPD is shown to outperform the state-of-the-art PW DPD based on the indirect learning architecture, as well as the classical single-polynomial-based DPD solutions in terms of linearization performance and computational complexity by a clear margin.
19 citations
23 May 1994
TL;DR: A novel technique is proposed for the measurements of the transducer power gain and noise figure of the amplifier embedded in a receiving active antenna, where the direct measurements with traditional techniques are impossible.
Abstract: A novel technique is proposed for the measurements of the transducer power gain and noise figure of the amplifier embedded in a receiving active antenna, where the direct measurements with traditional techniques are impossible. The bandwidth of the active antenna can be also determined with this technique. The good agreement between the measurements and calculations of a number of active receiving microstrip antennas shows the validity of the measurement technique. This makes it possible to characterize all the performance of receiving active antennas. >
18 citations
Patent•
02 Dec 2015
TL;DR: In this paper, a micro-spaceborne high-dynamic GNSS receiver and a navigation method are presented, which includes an active antenna, a radio frequency front end processing module, a baseband signal digital processing module and a positioning solution module, and a host computer monitoring interface.
Abstract: The invention discloses a micro spaceborne high dynamic GNSS receiver and a navigation method thereof. The receiver comprises an active antenna, a radio frequency front end processing module, a baseband signal digital processing module, a positioning solution module and a host computer monitoring interface. The navigation method comprises the steps that the active antenna converts a received GNSS electromagnetic wave signal into a current signal; the signal enters the radio frequency front end processing module through a band-pass filter, and undergoes amplification, frequency conversion, filtering and analog-to-digital conversion to finally acquire a digital intermediate frequency signal; the baseband signal digital processing module carries out capturing, tracking, bit synchronization and frame synchronization on the digital intermediate frequency signal to acquire a navigation measurement value and a navigation message; the positioning solution module carries out positioning solution to finally acquire the satellite information of a user; and the host computer monitoring interface displays a positioning observation value, the number of received satellites and the information of a PDOP value in real time. The micro spaceborne high dynamic GNSS receiver and the navigation method thereof have the advantages of high framework flexibility, rapid verification of an improved algorithm, low cost, small volume and light weight.
18 citations
TL;DR: In this article, a vision-based active sensing system is proposed, which consists of a camera, a flexible beam whose force-deformation characteristic is known, and an actuator for rotating the beam.
Abstract: Proposes a vision-based active sensing system, termed vision-based active antenna. This is composed of a camera, a flexible beam whose force-deformation characteristic is known, and an actuator for rotating the beam. The camera observes the beam deformation, including the contact information, while the beam is in contact with an object. By solving a set of equations based on the information acquired through the camera, the sensor can detect the contact location, the contact force, and the stiffness of the object, even though the contact point is hidden by occlusion. For two particular versions, we show some experimental results to verify the basic idea.
18 citations
TL;DR: In this paper, modal filtering was used to mitigate undesired reflections and improve the measurement result through postprocessing, which is applicable to integrated antenna measurements at frequencies over 100 GHz and that a significant improvement in the measured radiation pattern can be achieved.
Abstract: Feeding integrated antennas during a measurement requires special feeding structures Due to the small antenna dimensions, these feeding structures are often much bigger than the antenna under test (AUT) itself and with chip sizes of around 1 mm2, the achievable separation between antenna and feed is limited Wafer probes have to be used to feed the AUT during passive antenna measurements and present a large reflective surface in close proximity to the AUT Reflections from the wafer probe cause interference on the measurement surface and distort the results The same is true for active antenna measurements, where bondwires and the package can have a significant effect on the radiated fields The fragility and size of the components do not allow to reduce reflections with absorbers, which is why modal filtering was used in this paper to mitigate undesired reflections and improve the measurement result through postprocessing Two issues that limit the performance of the algorithm are discussed, namely, phase center inaccuracies of the AUT and a limited measurement surface It is shown that modal filtering is applicable to integrated antenna measurements at frequencies over 100 GHz and that a significant improvement in the measured radiation pattern can be achieved Furthermore, it is shown that the postprocessed results make it possible to measure the directivity of integrated antennas, despite strong probe reflections
18 citations