Integrated Tunable Cavity Gunn Oscillator for 60-GHz Operation in Image Line Waveguide

Abstract

.Abstract -The design, construction, and experimental test results of a mechanically tunable Gnnn oscillator using a recessed diode metaf coaxial cavity coupled to an image fine wavegnide is described. The oscillator frequency was changed by about lo-percent by varying the bias post length into the coaxial structure. The oscillator is designed so that troth the Gunn diode and resonant cavity can be quickly replaced to provide extended freqnency coverage and efficiency. Tlris Gunn diode oscillator has provided up to 15.mW CW power at 60 G!fz with 10-percent tuning range.

Design of Half Mode Substrate Integrated Waveguide Gunn Oscillator

“…The power output level is 13.2 dBm. The free running phase noise was measured according 10 [9], [15], [16], at millimeter wave band microstrip or waveguide fin-line Gunn oscillator' phase noise is relatively high, ranging from −87 to −70 dBc/Hz at an offset frequency of 100 kHz. Metal cavity resonator and NRD guide Gunn oscillator' phase noise is relatively low, ranging from −132 to −87 dBc/Hz at an offset frequency of 100 kHz, but they are not planar structures and their fabrication is relatively complex.…”

“…The equivalent circuit model for the Gunn oscillator [7]- [9] is shown in Fig. 3, where −G D· is the negative conductance of the Gunn diode, X a the capacitance of the parallel resonance, X b the inductance of the parallel resonance, B D· the equivalent admittance of the Gunn diode, Y D = −G D + B D is the equivalent admittance of Gunn diode, L s the down-lead wire inductance, C P the package capacitance, Y L the outputting loading admittance and Y L the transformed loading admittance with "n:1" impedance transformer of Y L .…”

Parallel type substrate integrated waveguide Gunn oscillator

“…The equivalent circuit model for the Gunn oscillator [7][8][9] is shown in Figure 3, where ϪG D is the negative conductance of the Gunn diode, B D the equivalent capacitance of the Gunn diode, L P the down-lead wire inductance, C p the package capacitance, and Y L the transformed load resistance. The values of L S and C P are inherent in the construction of the device, because the lead inductance from the top of the semiconductor surface to the top of the standoff package is always present.…”

“…In addition to the procedure proposed by Leach, Bucci [8] and Rahmatt-Samii [9] studied some improvements in the efficiency of this method. In the last years, some approaches to solve the problem of near to far-field transformation using equivalent currents have been presented [10 -14].…”