Active antenna

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

Active Phased Array Antenna with Self-Oscillating Harmonic Mixers

Abstract: The active phased array antenna with self-oscillating harmonic mixers has been investigated. The active antenna is composed of a patch antenna receiving RF signal and a parallel feedback type oscillator which operates as the self-oscillating harmonic mixer, and down-converts the received RF signal into IF signal. The oscillator has two ports for output of the oscillated power and for injection signal so that the oscillators can be coupled unilaterally without other nonreciprocal components. In the unilaterally coupled array, the phase differences between the local oscillating signals can be varied by changing the local free-running frequencies of the self-oscillating mixers. The receiving directivity can be controlled by combining the IF signals from the individual active antennas. In the experiment using the two-element array, the receiving pattern was scanned successfully.

Method for predicting passive interference resonant frequency of short-wave frequency band of ultra-high voltage transmission line

Abstract: The invention discloses a method for predicting a passive interference resonant frequency of a short-wave frequency band of an ultra-high voltage transmission line. The method comprises the following steps: enabling a system comprising an ultra-high voltage transmission line array tower and an active antenna in a wide-area space to be equivalent to an electromagnetic open system; on the basis of the complex poynting theorem, calculating electric field energy and magnetic field energy of the electrically large electromagnetic open system of the ultra-high voltage transmission line to obtain mathematical representations of the electric field energy and the magnetic field energy of the electromagnetic open system; obtaining the mathematical representations of total electromagnetic field energy and an equivalent impedance matrix of the electromagnetic open system on the basis of voltage and current of an antenna feed port of the electromagnetic open system; and obtaining a frequency point, namely predicted resonant frequency, when the electric field energy and the magnetic field energy are in balance according to conditions of generating the resonance of the electromagnetic open system. According to the method, the generation of the resonant frequency can be accurately predicted from the essence of energy conversion of the electromagnetic open system of the ultra-high voltage transmission line; and the method can be applied to the prediction of the passive interference resonant frequency of the short-wave frequency band of the ultra-high voltage transmission line in future.

Smart antenna system and method for improving receiving performance thereof

Abstract: A smart antenna system according to an exemplary embodiment of the present invention including a beam forming antenna which includes an active antenna and a plurality of parasitic antennas, the system including: a reactance load which is connected to the parasitic antenna; a transceiver which transmits and receives a signal to the beam forming antenna; and an antenna adjusting block which tracks a signal source in real time using a plurality of beam patterns having the largest signal size and forms a beam in a direction having the largest signal size.

Active antenna development for the SKA

Abstract: The Square Kilometre Array (SKA) will be the most sensitive radio telescope ever built It is divided into three operating bands Sparse aperture arrays (SKA-low) are used at the lowest operating band of 70 – 450 MHz The International Centre for Radio Astronomy (ICRAR) is exploring conical spiral antennas as one candidate antenna design for SKA-low One of the attractive features of the conical spiral antenna is its frequency-stable impedance This helps in matching it to external components such as a low-noise amplifier (LNA) A prototype LNA based on GaAs HEMT technology that might be suitable for the conical spiral antenna has been evaluated Presented in this paper is the current design path for a conical spiral antenna with attached LNA

Power supply circuit for an active antenna of a vehicle radio

Abstract: A power supply circuit provides power to an antenna amplifier (4) of a vehicle radio via the antenna bushing (A) and the antenna cable (6). The circuit is resistant to short-circuits and has a pair of signal terminals (K2, K3) from which information, about the type of attached antenna and about its operating state, can be picked up.