情報化社会の発展に伴い、ワイヤレス送受信の多様化とニーズが拡大し、高速・大容量の通信が必要となり、より高いマイクロ波・ミリ波周波数帯が通信に使われ、部品も小型、高性能、低コストなものが要求されるようになった。 本研究では、これらの課題を解決するために、-発振原理を用いた構成の発振回路を研究している。この原理を用いる事で、低コストで高品質な高周波発振器を構成できる。 この発振器にあらゆるデバイス素子、回路を複合化等を行う事で発振回路の高性能化について検討した。

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In this paper, the 8th harmonic - oscillator is successfully presented. The - 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 - oscillator has practical advantages of the easy circuit design due to the simple circuit configuration and the miniaturization of the circuit size. Using the - principle and the effective circuit configuration of the output circuit, the desired 8th harmonic signal is effectively enhanced. This - oscillator achieves good millimeter-wave oscillation in V band using inexpensively available X band HEMTs. The estimated output power of -6dBm at the frequency of 51GHz is obtained with the phase noise of -93dBc/Hz at the offset frequency of 1MHz.

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研究では、両平面回路構造を用いた正帰還型-発振器の広帯域VCO化について検討した。-発振器にはHEMTを用いており、基本周波数波と奇数次高調波を抑圧し第2次高調波を出力させる。周波数可変機能は帰還ループ中にπ/2ハイブリッド回路を用いた可変移相器を組み込むことによって実現している。その結果、Ku帯で約1.2GHzの広帯域な周波数可変性を実証した。

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In this paper, a positive feedback - oscillator array for beam steering antenna is proposed. The oscillator array consists of the positive feedback - oscillators and the directional phase shifters. The phase shifter consists of a π/2 hybrid circuit and varactor diodes. The phase shifter gives the phase difference between the adjacent oscillators. It is possible to control the output phase difference of the oscillators by the tuning voltage of varactor diodes.

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In this paper, a compact microwave

- oscillator based on a resonant tunneling diode (RTD) has been fabricated and demonstrated. A symmetrical spiral inductor structure has been used in order to reduce a chip area. The designed symmetric inductor is integrated into the InP-based RTD monolithic microwave integrated circuit (MMIC) technology. The circuit occupies a compact active area of 0.088 mm² by employing symmetric inductor. The fabricated RTD oscillator shows an extremely low DC power consumption of 87 µW at an applied voltage of 0.47 V with good figure-of-merit (FOM) of -191 dBc/Hz at an oscillation frequency of 27 GHz. This is the first implementation as the RTD - oscillator with the symmetrical spiral inductor.

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In this paper, a wide band positive feedback - VCO using Double-Sided MIC technology is presented. The second harmonic signal is the desired output. The fundamental signal and the odd harmonics are suppressed in principle. Phase shifters are arranged in the positive feedback circuit effectively. Wide frequency tuning rang has been achieved by the use of compact phase shifters.

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Recently, an electronically scanned phased array systems have attracted much interest. However, the phased array systems have very complicated structure and then they are still expensive. A - oscillator array is very effective for these solutions. In this paper, a novel oscillator array using positive feedback - oscillators for a beam steering antenna is proposed

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An injection locked coupled - 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 - 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 - 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 - 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.

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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.

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近年の無線通信においては,周波数不足の克服と大容量高速データ伝送を満足するためにマイクロ波・ミリ波などの高い周波数帯が用いられるようになり、その結果,高周波発振器の重要性が高まっている.その課題としては,低雑音化や高出力化などがあり,さらに小型化や低コスト化などがある.これらの課題の解決策の1つとして,-発振回路の研究が進められている.ここでは,2つの-発振回路をRF乗算回路を介して同期接続し,相互の信号の位相差を固定することによってその位相雑音を低減することを試みている.

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In this paper, a - oscillator array using variable phase shift coupling circuit is presented. The oscillator array consists of a reflection-type - oscillators and variable phase shift coupling circuit. The variable phase shift coupling circuit consists of a CPW resonator and varactor diodes. The phase shift between the output signals of the neighboring oscillators is controlled by the phase difference of the reflection coefficients of the coupling circuit. The basic performance of the oscillators array using two - oscillators is confirmed.

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In this letter, a wideband - VCO using two types of phase shifters is presented. A positive feedback type - 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 - 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.

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This letter presents a 48 GHz frequency doubler in a 65 nm CMOS technology. The proposed frequency doubler is composed of a complementary

- structure with negative resistance circuit for conversion gain enhancement. The maximum measured conversion gain reaches −6.1 dB at 48 GHz output frequency, and the 3-dB bandwidth is 40∼54 GHz. The fundamental rejection is above 29.5 dB. The size of the proposed frequency doubler chip is 0.72 × 0.36 mm². The total power consumption is 16 mW.

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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 +8.89dBm at the design frequency of 18.75GHz (2f₀) with the phase noise of -116.2dBc/Hz at the offset frequency of 1MHz. Excellent suppression of the undesired fundamental frequency signal (f₀) of -33dBc is achieved. Also, the circuit size is reduced by three-tenths relative to that of the previously proposed circuit.

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In this paper, a positive feedback type - oscillator array using injection locking technology is presented. It is confirmed that the phase noise of the output signal is improved by the injection signal.

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A novel reflection-type - oscillator array is presented. The oscillator array consists of N oscillator and (N-1) coupling circuit. The coupling circuit has two ports to connect neighboring oscillators. Structure of the coupling circuit is unsymmetrical and the scattering parameter (S11) is constant, on the other hand, S22 is variable. Due to the variable S22, a variable phase difference of the output signals can be realized.

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本研究では,両平面回路構造を用いた周波数可変正帰還型-発振器の広帯域化について検討した.-発振器には2個のHEMTを用いており,基本波を含む奇数次高調波を抑圧し第二次高調波を出力させる.周波数可変機能は正帰還型-発振器の正帰還共通スロット部に移相器を組み込むことで実現する.その結果,K帯で3GHz(比帯域12.9%)の広帯域な周波数可変性を実証した.

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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 - 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 0.18µm CMOS process. The core power consumption of the ILFD core is 3.12mW. The divider's free-running frequency is tunable from 4.26GHz to 4.9GHz by tuning the varactor's control bias, and at the incident power of 0dBm the locking range of the ILFD used as a divide-by-3 divider is 1.5GHz, from 12.5GHz to 14.0GHz.

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