IEEE MTT-S 2008 International Microwave Symposium Technical Program

Session: THP2A	Interactive Forum:
Chair:	Daniela Staiculescu, Georgia Institute of Technology
Co-Chair:	Ronglin Li, Georgia Institute of Technology

THP2A-01	Microwave Pulse Generation Using the Bragg Cutoff of a Nonlinear Transmission Line
1137	K. G. Lyon, E. C. Kan, Cornell University, Ithaca, United States
	Nonlinear transmission lines (NLTL) have received considerable attention for their frequency conversion, fast pulse generation, and rise/falltime compression properties. Here we present a new mode of operation for the NLTL which uses falltime compression to generate short RF pulses near the Bragg cutoff frequency. While this phenomenon has been reported in circuit model simulations, we demonstrate, to our knowledge, its first experimental verification. We demonstrate control of the pulse center frequency using next-nearest neighbor coupling and examine the feasibility of MMIC implementation. Our resulting devices generate short microwave pulses suitable for short range wireless communication. The frequency conversion is non-harmonic and requires no active bias currents.

THP2A-02	An Eight-Phase Voltage Controlled Oscillator with Reflection-Type Modulators in 0.18-μm CMOS Technology
1451	C. Lin, H. Chang, National Central University, Jhongli City, Taiwan
	This paper describes a fully integrated eight-phase voltage controlled oscillator (VCO) monolithic microwave integrated circuit (MMIC) with reflection-type modulators in 0.18-m CMOS Technology. The characterization of the amplitude and phase errors is successfully demonstrated using the proposed innovative method. The eight-phase VCO achieves a low phase noise of -117.1 dBc/Hz at 1-MHz offset frequency. For the characterization of the amplitude and phase errors, this circuit features a sideband suppression of better than -26 dBc and a LO suppression of better than -18 dBc. From the sideband suppression contours, the measured amplitude and phase errors of the eight-phase VCO are within 0.85 dB and 5º, respectively. To the best of the authors’ knowledge, this work is first attempt to demonstrate the characterization of the amplitude and phase errors for the eight-phase VCO.

THP2A-03	Low Phase Noise VCO Using Microstrip Square Open Loop Multiple Split Ring Resonator
1488	J. Choi, C. Seo, Soongsil University, Seoul, Republic of Korea
	In this paper, a novel voltage-controlled oscillator (VCO) using the microstrip square open loop multiple split ring resonator (OLMSRR) is presented for reducing the phase noise. The square-shaped multiple split ring resonator (MSRR) having the form of the microstrip square open loop is investigated to realize this purpose. Compared with the conventional microstrip line resonator and the microstrip square open loop resonator, the microstrip square OLMSRR has the larger coupling coefficient value, which makes a higher Q value, and has reduced the phase noise of VCO. The proposed VCO has the phase noise of -124.5 ~ -122.0 dBc/Hz @ 100 kHz in the tuning range, 5.746 ~ 5.84 GHz. The figure-of-merit (FOM) of this VCO is -203.96 ~ -201.6 dBc/Hz @ 100 kHz in the same tuning range. Compared with VCOs using the conventional microstrip line resonator and the microstrip square open loop resonator, the phase noise property of the proposed VCO has been improved in 25.66 dB and 8.34 dB.

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