Phased Array Behavior of Unilaterally Coupled Active Antennas with Varactor Diodes

Minoru SANAGI  Tomomichi KAGAWA  Shigeji NOGI  

IEICE TRANSACTIONS on Electronics   Vol.E86-C    No.2    pp.192-198
Publication Date: 2003/02/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Circuit and Device Technology for High-Speed Wireless Communication)
Category: Antenna (Active)
microwave,  active antenna,  phased array,  injection locking,  

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A phased array behavior of a unilaterally coupled active antennas has been investigated. The active antenna is composed of a patch antenna and a parallel feedback type oscillator which can be coupled unilaterally to other oscillators without other nonreciprocal components. Numerical calculations of the reduced equations describing the behavior of the coupled oscillators array demonstrated that the phase differences between the oscillators can be varied up to about π/2 by giving the frequency changes from the injection locking frequency to the oscillators except of the first one. The oscillator mounted with the varactor diode for wide tuning range exhibited the property suitable for constructing the unilaterally coupled array. In the experiments at X-band, the electromagnetic wave radiated from the five element array was successfully scanned.