Low Noise Second Harmonic Oscillator Using Mutually Synchronized Gunn Diodes

Kengo KAWASAKI  Takayuki TANAKA  Masayoshi AIKAWA  

IEICE TRANSACTIONS on Electronics   Vol.E93-C   No.9   pp.1460-1466
Publication Date: 2010/09/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E93.C.1460
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Microwaves, Millimeter-Waves
Gunn oscillator,  active resonator,  microwave integrated circuit,  microwave oscillator,  

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This paper represents a low noise second harmonic oscillator using mutually synchronized Gunn diodes. A multi-layer MIC technology is adopted to reduce the circuit size of the oscillator. The oscillator consists of Gunn diodes, slot line resonators and strip lines. By embedding Gunn diodes in the slot line resonators, a harmonic RF signal can be generated very easily. The strip lines are used for the power combining output circuit. The shape of slot line resonator is square in order to achieve the low phase noise and the suppression of undesired harmonics. The second harmonic oscillator is designed and fabricated in K band. The output power is +8.89 dBm at the design frequency of 18.75 GHz (2f0) with the phase noise of -116.2 dBc/Hz at the offset frequency of 1 MHz. Excellent suppression of the undesired fundamental frequency signal (f0) of -33 dBc is achieved. Also, the circuit size is reduced by three-tenths relative to that of the previously proposed circuit.