Kengo Kawasaki

A novel K-band push-push oscillator using slot ring resonator embedding Gunn diodes

In this paper, a novel Gunn diode push-push oscillator is proposed. Gunn diodes and a slot ring resonator are used for the oscillator. A double-sided circuit technology is adopted successfully. The oscillator consists of four Gunn diodes, a slot ring resonator and microstrip lines for the output circuit. The Gunn diodes are arranged on the slot ring resonator formed on a dielectric substrate. The microstrip lines, output circuit is formed on the reverse side. The oscillator is designed and fabricated in K-band. The measured output power of the desired second harmonic signal is +3.16 dBm at the frequency of 19.2 GHz. The measured phase noise is -108.5 dBc/Hz at 1 MHz offset frequency. The oscillator is designed easily due to the very simple structure and achieves low phase noise performance with low cost by using the advantages of Gunn diode oscillator.

Ku band second harmonic N-coupled push-push oscillator array using microstrip resonator

This paper presents the second harmonic push-push oscillator array. By using the push-push oscillator, a high frequency signal is easily generated with inexpensive low frequency devices. These push-push oscillators are connected with coupling circuits which are composed of microstrip resonators. The coupling circuit has two ports to connect the push-push oscillators. The reflection constant, S11 and S22, of the coupling circuit are controlled by a varactor diode. In the coupling circuit, the phase of S11 is almost constant, and the other S22 is changed by the reactance of the varactor diode. Therefore, the output signals of the push-push oscillators are generated with different phase. The second harmonic push-push oscillator array is designed and fabricated in Ku band. The basic performance of the oscillator array using two push-push oscillators is basically investigated. The phase shift introduced between two oscillators is 451 degrees at 14.75 GHz. The output power of the second harmonic signal is +0.67 dBm with the phase noise of −107.5 dBc/Hz at the offset frequency of 1 MHz.

V-band 8th harmonic push-push oscillator using microstrip ring resonator

In this paper, the 8th harmonic push-push oscillator is firstly presented. A push-push principle is applied in this oscillator. The proposed push-push oscillator consists of two sub-circuits, a microstrip ring resonator, and an output circuit. A simplified circuit configuration is adopted in the proposed oscillator. The microstrip ring resonator plays two roles of a resonator and a power combiner circuit. This kind of push-push oscillator has the advantages of the easy circuit design, the simple circuit configuration and the miniaturization of the circuit size. Using the effective circuit configuration of the output circuit, a desired 8th harmonic signal is successfully enhanced. This push-push oscillator achieves high quality V-band millimeter wave oscillation using inexpensively available X-band HEMTs. The measured output power of −12 dBm at the frequency of 51 GHz is obtained with the phase noise of −94 dBc/Hz at the offset frequency of 1 MHz.

K-Band Second Harmonic Oscillator Using Mutually Synchronized Gunn Diodes Embedded on Slot Line Resonators

This paper represents a novel second harmonic power combining oscillator using mutually synchronized Gunn diodes embedded on slot line resonators. A both-sided MIC technology is adopted in the oscillator. The oscillator consists of Gunn diodes, slot line resonators and microstrip lines. By embedding Gunn diodes on the slot line resonators, the harmonic RF signal can be generated very easily. The microstrip lines are used for the power combining output circuit. This oscillator has advantages such as easy circuit design, simple circuit configuration and miniaturization of the circuit size. The second harmonic oscillator is designed and fabricated in K-Band. The output power is +5.75dBm at the design frequency of 19.0GHz (2f0) with the phase noise of -111.7dBc/Hz at the offset frequency of 1MHz. Excellent suppression of the undesired fundamental frequency signal (f0) of -39dBc is achieved.

A push-push VCO using a phase shifter with 90° branch line hybrid circuit

In this paper, a wideband push-push VCO using a phase shifter is presented. The phase shifter consists of a 90˚ branch line hybrid circuit and varactor diodes. The oscillator is a positive feedback type oscillator. In the oscillator, the oscillating frequency can be changed by using the phase shifter as the electrical length of the feedback loops determine the oscillating frequency. The circuit structure is very simple and compact due to the double-sided MIC structure. This type of push-push oscillator is suitable for a wideband VCO compared with a negative resistance type one. In the experiment, the developed push-push VCO in Ku-band achieves wide tuning frequency range of 1.2 GHz (relative bandwidth =7.5%).

A Push-Push Oscillator Array Using Resonator Type Coupling Circuits

A coupled oscillator array using push-push oscillators and resonator type coupling circuits is presented. In the proposed oscillator array, the coupling circuit operates at the fundamental frequency and the output signal is the 2nd harmonics. The adjacent oscillators are connected via the coupling circuits. The coupling circuit is used to synchronize the oscillators and control the phase difference of the output signals. In this study, a three elements push-push oscillator array has been designed in Ku band. The measured phase shift between the output signals of the adjacent oscillators is 511 degrees at the maximum.

A positive feedback type push-push VCO using series connected phase shifters

In this letter, a wideband push-push VCO using two types of phase shifters is presented. A positive feedback type push-push oscillator is used for the VCO. The phase shifters are connected in series in each feedback loop. Varactor diodes are used in the phase sifters for the frequency tuning. In the VCO, the oscillating frequency can be changed widely as much phase shift is achieved by the sum of phase shift of each phase shifter connected in series. In the experiment, the developed push-push VCO designed in K-band achieves wide tuning frequency range of 1.88GHz(relative bandwidth = 8.9%) in K-band with small variation of the output power.

Low noise second harmonic Gunn diode oscillator using square-shaped slot line resonator

This paper presents a low noise second harmonic Gunn diode oscillator using square-shaped slot line resonator. 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 microstrip lines. The Gunn diodes are embedded in the slot line resonators. The output circuit is formed using the microstrip line. A second harmonic signal can be obtained from the output circuit. A square-shaped slot line resonator is used 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 1MHz. Excellent suppression of the undesired fundamental frequency signal (f0) of −33dBc is achieved. Moreover, the circuit size is reduced by three-tenths relative to that of the previous model of the proposed oscillator.

An Octa-Push Oscillator at

In this paper, an octa-push oscillator is first presented. An N-push oscillator principle is effectively adopted. The proposed oscillator consists of eight sub-circuits, a microstrip ring resonator, and an output circuit. The microstrip ring resonator plays the role of both resonator and power-combiner circuit. This oscillator has the advantages of easy circuit design and the miniaturization of the circuit size due to the simple circuit configuration. The oscillator generates the output signal, utilizing the electromagnetic resonant field in the resonator. Based on the N-push principle, the desired eighth harmonic signal is successfully obtained. This octa-push oscillator achieves high-quality millimeter-wave oscillation in V-band using inexpensively available X-band devices. The measured output power of -4 dBm at a frequency of 51 GHz is obtained with the phase noise of -100 dBc/Hz at the offset frequency of 1 MHz.