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Kengo KAWASAKI Takayuki TANAKA Masayoshi AIKAWA
An injection locked coupled push-push 3-oscillators array using unilateral coupling circuits is proposed. The circuit consists of unit oscillators and coupling circuits. For the unit oscillator, a dual-band push-push oscillator which generates the fundamental signal (f0) and the second harmonic signal (2f0) is adopted. The output signal of the oscillator array is the second harmonic signal. The fundamental signal is used for the injection signal to synchronize oscillators. These adjoining unit oscillators are connected by the coupling circuits. The coupling circuit is composed of a buffer amplifier and a phase shifter. Due to the advantage of the push-push oscillator, the phase shift between the adjoining oscillators is twice as large as that of the phase shift in the coupling circuit. The oscillator array is designed in Ku-band. Three push-push oscillators are arrayed and include two coupling circuits which are designed and fabricated. The phase shift of 190.0 degrees between the adjoining unit oscillators is demonstrated.
Sheng-Lyang JANG Chia-Wei CHANG Yu-Sheng CHEN Jhin-Fang HUANG Jau-Wei HSIEH Chong-Wei HUANG
A novel divide-by-3 injection-locked frequency divider (ILFD) is proposed. The ILFD circuit is realized with a cross-coupled n-core MOS LC-tank oscillator embedded with a push-push signal generator and two injection MOSFETs for coupling the injection signal into the resonator. The ILFD uses the linear mixer to extend the locking range and has been implemented in a standard 0.18 µm CMOS process. The core power consumption of the ILFD core is 3.12 mW. The divider's free-running frequency is tunable from 4.26 GHz to 4.9 GHz by tuning the varactor's control bias, and at the incident power of 0 dBm the locking range of the ILFD used as a divide-by-3 divider is 1.5 GHz, from 12.5 GHz to 14.0 GHz.
Kengo KAWASAKI Takayuki TANAKA Masayoshi AIKAWA
In this paper, the 8th harmonic Push-Push oscillator is successfully presented. The Push-Push principle and the excellent harmonic coherency in a microwave resonator are effectively utilized. The proposed oscillator consists of two sub-circuits, a microstrip ring resonator and an output circuit. The concept of the simplified structure harmonic oscillator (SSHO) is adopted in the proposed oscillator. The microstrip ring resonator plays two roles of the common resonator and the power combiner circuit. This kind of Push-Push oscillator has practical advantages of the easy circuit design due to the simple circuit configuration and the miniaturization of the circuit size. Using the Push-Push principle and the effective circuit configuration of the output circuit, the desired 8th harmonic signal is effectively enhanced. This Push-Push oscillator achieves good millimeter-wave oscillation in V band using inexpensively available X band HEMTs. The estimated output power of -6 dBm at the frequency of 51 GHz is obtained with the phase noise of -93 dBc/Hz at the offset frequency of 1 MHz.
Hai XIAO Takayuki TANAKA Masayoshi AIKAWA
A novel millimeter wave quadruple-push oscillator is presented in this paper. The quadruple-push oscillator consists of four identical sub-circuits and a ring resonator that is used as a common resonator. It is well known that there are two orthogonal resonant modes on a one-wavelength ring resonator. According to this resonant characteristic, two orthogonal push-push oscillations can be set up in the quadruple-push oscillator, and there is a phase difference of 90among four sub-circuits due to nonlinear performance. Therefore, the four identical sub-circuits can oscillate at the same fundamental frequency f0, and the fundamental oscillating signal of one sub-circuit has phase differences of 90, 180and 270to that of the others, and the desired fourth harmonic signals can be combined due to their in phase relations, and the undesired fundamental signals, the second harmonic signals, the third harmonic signals and so on can be suppressed when the oscillating signals of the four sub-circuits are added in phase. The principle is firstly explained in this paper, and is proved in the experiment of a Ka-band quadruple-push oscillator. The measured output power of the desired fourth harmonic signal (4f0) was +1.67 dBm at the frequency of 35.8 GHz. The measured suppression of the undesired signals of the fundamental signal (f0), the second harmonic signal (2f0), the third harmonic signal (3f0) and the fifth harmonic signal (5f0) were -18.0 dBc, -17.9 dBc, -17.8 dBc and -35.5 dBc, respectively. The measured phase noise performances at 35.8 GHz were -104.0 dBc/Hz and -82.3 dBc/Hz at the offset frequency of 1 MHz and 100 kHz, respectively.
Hai XIAO Takayuki TANAKA Masayoshi AIKAWA
In this paper, a 20 GHz push-push oscillator using a ring resonator is proposed. The push-push oscillator adopts "dipole resonator push-push oscillator" circuit scheme, in which a common resonator plays two roles of frequency determining and power combining, and then the additional power combiner circuit required in conventional push-push oscillators can be eliminated. This kind of push-push oscillators has the advantages of the easy circuit design, the simple circuit configuation and the miniaturization of the circuit size. The output power is +4.5 dBm at the frequency of 20.34 GHz (2f0) with the phase noise of -98 dBc/Hz at the offset frequency of 1 MHz, and a high suppression of the undesired the fundamental frequency signal (f0) of -33 dBc is obtained.
Kenji KAWAHATA Takayuki TANAKA Masayoshi AIKAWA
A novel push-push oscillator taking advantages of "Double-Sided MIC Technology" is proposed. The oscillator incorporates microstrip lines on a dielectric substrate and a slot line on the reverse side. By integrating a slot line and microstrip lines, the push-push oscillator can be realized very easily. All the concerned undesired harmonic signals (f0, 3f0 and 4f0) can be suppressed satisfactorily. Using these approaches, a push-push oscillator in K-band is designed and fabricated. The output power of +4.17 dBm at the frequency of 21.25 GHz is measured. All the undesired signals are sufficiently suppressed to be better than -30 dBc. The phase noise is -99.68 dBc/Hz at the offset frequency of 1 MHz.
Hai XIAO Takayuki TANAKA Masayoshi AIKAWA
In this paper, a novel circuit structure of Push-Push oscillator using λg/2 microstrip resonator is proposed, in which a common resonator plays two functions of frequency determining and power combining. This type of Push-Push oscillator is named "Dipole Resonator Push-Push oscillator" here, where an additional power combiner circuit required in conventional Push-Push oscillators can be eliminated. The Push-Push oscillator adopting this design concept has the advantages of the easy circuit design, the simple circuit structure and the miniaturization of the circuit size. As a most simple example of this design concept, a K-band Push-Push oscillator using a λg/2 microstrip resonator is designed and achieved. The high output power of +8.4 dBm at the frequency of 21.68 GHz (2f0) is obtained with the phase noise of -100.5 dBc/Hz at the offset frequency of 1 MHz. Besides, a high suppression of the undesired fundamental frequency signal (f0) of -26 dBc is realized.