• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.6
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• pp.682-690
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• 2012

In this paper, a highly linear self oscillating mixers(SOM) using second harmonic injections are presented. The H-slot defected ground structure(DGS) is designed as a balanced resonator for oscillation in the proposed SOM. Since the H-slot DGS resonator achieves a high Q factor, it is a suitable structure to provide low phase noise for the oscillator. The single balanced mixer is utilized in this work and it provides good LO-RF isolation since balanced LO signals are suppressed at the RF input port. In order to inject the second harmonic of the IF, we propose two different methods using feedback loops. In the first method, IF achieves a 3.08 dB conversion gain at 226 MHz with input power of -20 dBm at 5 GHz RF input signal. The IF achieves 2 dB conversion gain at 423 MHz with the input power of -20 dBm at 5.2 GHz RF input signal in the second method. The measured IMD3s are 61.8 dB and 65 dB for the each method. These SOMs present improved linearity compared to that without the second harmonic injection because IMD3s are improved by 18. dB and 21 dB for each method.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2182-2186
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• 2003

This paper presents the differential type resonant accelerometer (DRXL) and its performance test results. The DRXL is the INS grade, surface micro-machined sensor. The proposed DRXL device produces a differential digital output upon an applied acceleration, and the principle is a gap-dependent electrical stiffness variation of the electrostatic resonator with torsion beam structures. Using this new operating concept, we designed, fabricated and tested the proposed device. The final device was fabricated by using the wafer level vacuum packaging process. To test the performance of the DRXL, a nonlinear self-oscillation loop is designed using describing function technique. The oscillation loop is implemented using discrete electronic elements. The performance test of the DRXL shows that the sensitivity of the accelerometer is 12 Hz/g and its long term bias stability is about $2mg(1{\sigma})$. The turn on repeatability, bandwidth, and dynamic range are 4.38 mg, 100 Hz, and ${\pm}\;70g$, respectively.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.5
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• pp.1-10
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• 1998

A GaAs MMIC composed of VCO (voltage controlled oscillator) and mixer for PCS receiver has been developed using 1.mu.m ion implanted GaAs MESFET process. The VCO consists of a colpitts-type oscillator with a dielectric resonator and the circuit configuration of the mixer is a dual-gate type with an asymmetric combination of LO and RF FETs for the improvement of intermodulation characteristics. The common-source self-biasing is used in all circuits including a buffer amplifier and mixer, achieving a single power supply (3V) operation. The total power dissipation is 78mW. The VCO chip shows a phase noise of-99 dBc/Hz at 100KHz offset. The combined VCO/mixer chip shows a flat conversion gain of 2dB, the frequency-tuning factor of 80MHz/volts in the varacter bias ranging from 0.5V to 0.5V , and output IP3 of dBm at varactor bias of 0V. The fabricated chip size is 2.5mm X 1.4mm.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.697-700
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• 1999

This Paper presents the design, fabrication, analysis of the measured date of a voltage controlled oscillator(VCO) for the application of Personal Communication Systems. Main VCO circuit consists of self biased emitter resonating circuit with microstrip line resonator on FR4 epoxy substrate. A varactor diode is used for 90MHz frequency tuning with center frequency of 1635MHz Phase noise of -114.67㏈C/Hz at 100KHz off set has been achieved with 3.3 V supply. The size of the fabricated VCO circuit is 1.25 cm$\times$ 1.25 cm.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.9
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• pp.1108-1114
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• 1988

Usng the P.Yeh's analytic method, we derive the condition for oscillation of a linear phase conjugate oscillator which consists of photorefractive medium and two conventional mirrors. From this general oscillation condition, we obtain the threshold oscillation conditon of a single phase conjugate resonator and the self-oscillation condition of photorefractive medium, then in special case (phase shift =90\ulcorner: no external dc electric field), oscillation conditions of the linear phase conjugate oscillator for any cavity length are derived. The results indicate that, unlike in a phase conjugate oscillator with Kerr-like medium, oscillation cannot occur at special cavity length for given couplinyg strengths.

• Journal of the Korean Institute of Telematics and Electronics
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• v.3 no.4
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• pp.16-24
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• 1966

The LASER Amplifier is treated in the manner of a Fabry-Perot Resonator with an active media, five layers are considered: air, reflector, active medium(ruby), reflector and air. One dimensional scalar wave equations are derived using the method of boundary value probrems in which it is assumed that incident coherent radiation falls normally on the surface wall. All equations are treated from the transient analysis point of view using the Laplace transform nethods, and are arranged steady state region as an amplifier and transient region as a self excited oscillator. Also some remarks are given on the design problem of LASER amplifier in connection with the transient terms involved.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.4
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• pp.261-266
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• 1998

In developing the high density memory device, the etching of fine pattern is becoming increasingly important. Therefore, definition of ultra fine line and space pattern and minimization of damage and contamination are essential process. Also, the high density plasma in low operating pressure is necessary. The candidates of high density plasma sources are electron cyclotron resonance plasma, helicon wave plasma, helical resonator, and inductively coupled plasma. In this study, planar type magnetized inductively coupled plasma etcher has been built. The density and temperature of Ar plasma are measured as a function of rf power, flow rate, external magnetic field, and pressure. The oxide etch rate and selectivity to polysilicon are measured as the above mentioned conditions and self-bias voltage.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.224-228
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• 2002

In this study, the piezoelectric ceramics PZT powder was synthesized by the Wet-Dry combination method. Flexible 1-3 type composite specimens were fabricated with the piezoceramics PZT filler phase and Eccogel polymer matrix phase. This paper represents the pulse-echo response of the 1-3 type composite transducer to check it out to investigate a basic property regarding a level limit switch. The acoustic impedance of 1-3 type composite was improved than that of single phase PZT ceramics. The pulse-echo response of transducer fabricated with the self-made 1-3 type composites resonator was better than that of the solid PZT transducer.

• Journal of the Optical Society of Korea
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• v.14 no.1
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• pp.38-41
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• 2010

We design and fabricate a widely tunable laser diode made of InGaAsP-InP. The diode is monolithically integrated with a wavelength-selective coupled-ring reflector and semiconductor amplifiers. For realization of a compact size device, deeply etched multi-mode interference couplers and square ring resonators composed of total-internal-reflection mirrors are adopted and fabricated using a self-aligned process. It is demonstrated that the laser diode exhibits single mode operation and 16 nm tuning range with side-mode-suppression-ratio exceeding 20 dB.

• 전자공학회논문지 IE
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• v.47 no.4
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• pp.1-9
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• 2010

This paper describes a ultrasonic signal processing front-end IC for distance range meter and body detector. The burst shaped ultrasonic signal is generated by a self oscillator and its frequency range is about 40[kHz]-300[kHz]. The generated ultrasonic signal transmit through piezo resonator. The another piezo device transduce from received ultrasonic signal to electrical signals. This front-end IC contained low noise amplifier, band pass filter, busrt detector and time pulse generator and so on. This IC has two type of new idea for improve function and performance, which are self frequency control (SFC) and Variable Gain Control amplifier (VGC) scheme. The dimensions and number of external parts are minimized in order to get a smaller hardware size. This device has been fabricated in a O.6[um] double poly, double metal 40[V] High Voltage CMOS process.