IEEE MTT-S 2008 International Microwave Symposium Technical Program

Session: THP2H	Interactive Forum:
Chair:	Daniela Staiculescu, Georgia Institute of Technology
Co-Chair:	Ronglin Li, Georgia Institute of Technology

THP2H-01	On the Cyclostationary Properties of the 1/f Noise of Microwave Semiconductor Devices
1076	A. A. Lisboa de Souza, J. Nallatamby, M. Prigent, J. Obregon, XLIM - Université de Limoges, Brive, France
	This paper addresses, from an experimental perspective, the long-standing question on whether the 1/f noise of microwave semiconductor devices should be considered cyclostationary in compact models. By using a simple instrumentation setup and basic mixer concepts, it will be shown that the external equivalent current noise sources of such devices simply CANNOT be stationary. To demonstrate our ideas, a through experimental analysis was carried out on purely-resistive bridge circuits made up of microwave varactors and transistors under large-signal operation whose DC current component is kept constant. When computing the voltage noise power of specific circuit arrangements, errors in excess of 20dB may be induced if the stationary concept is adopted. The difference between the stationary or cyclostationary concepts will be simulated with the aid of the simulator ADS from Agilent.

THP2H-02	Mapping of Passive Intermodulation Products on Microstrip Lines
1270	A. P. Shitvov, D. E. Zelenchuk, A. G. Schuchinsky, V. F. Fusco, N. B. Buchanan, Queen's University of Belfast, Belfast, United Kingdom
	A new approach to the direct observation of third-order passive intermodulation (PIM3) products on the microstrip transmission lines is proposed. Mapping of PIM3 product distributions along printed microstrip traces and nearby localised sources has been realised with the aid of near-field probing and a standard PIM analyser. The results of PIM3 measurements are presented and discussed in comparison with simulations based on a nonlinear transmission line model (NTL) as well as earlier experimental studies.

THP2H-03	Measurement of Polarized Nano-Material (PNM) for Microwave Applications
1296	W. Chen¹, Z. Zhang¹, Z. Feng¹, Y. Chen¹, K. Jiang², S. Fan², M. Iskander³, ¹State Key Lab on Microwave & Digital Communication, Beijing, China, ²Tsinghua-Foxconn Nanotechnology Center, Beijing, China, ³Center for Advanced Communications, Honolulu, United States
	Study on a novel polarized nano-material (PNM) textile for microwave application has been carried out in this paper. Based on the PNM textile fabricated by Tsinghua-Foxconn Nanotechnology Center, we set up a waveguide test bed to evaluate different kinds of polarized PNM samples. In this paper, Crossed polarized, horizontal polarized and vertical polarized samples (all in waveguide) have been measured in the proposed test bed respectively. Experimental results show the polarization of the nanotube has dominant effect on the performance. The vertical polarized sample has the best performance in shielding effectiveness, the isolation between the two ports of the transmission waveguide is better than 15dB in average by using 20 layers of PNM yarns, and the horizontal polarized sample is almost invisible. This experiment gives a much deeper sight on the electromagnetic shielding principle of the nanotube materials, and will advance the application of PNM materials in many fields.

THP2H-04	Characterization of Galileo Signal Correlation Losses Caused by Non Linear Power Amplification with Memory
1410	G. Nanfack Nkondem¹, J. Santiago², G. Neveux¹, D. Barataud¹, J. Collantes², J. Portilla², J. Nebus¹, A. Mallet³, ¹XLIM, Limoges, France, ²Basque Country university, Bilbao, Spain, ³Cnes, Toulouse, France
	This paper presents a set up and a measurement data processing method applied to the characterization of non linear power amplifiers driven by Galileo modulation schemes for radio navigation application. The work reported here focuses on the impact of power amplifiers with memory on autocorrelation losses of Galileo signals. A hibrid MESFET amplifier having 17 dB power gain, 1 watt output power and 60% PAE has been characterized at 1.19 GHz with a signal bandwidth varying from 100KHz to 80 MHz.

THP2H-05	Microwave Properties of Platinum Nanoparticle Films
1419	A. Sulaimalebbe¹, A. Porch¹, G. Attard², F. Vidal-Iglesias², ¹Cardiff University, Cardiff, United Kingdom, ²Cardiff University, Cardiff, United Kingdom
	The electrical properties of platinum (Pt) nanoparticle films have been investigated experimentally using a microwave coaxial reflectance probe up to 6 GHz, for films composed of 26 nm and 11 nm particles. Larger particle films exhibit a conductive response, but with conductivity hugely suppressed (by a factor of 10^5) compared to bulk Pt. Smaller particle films exhibit an even greater suppression of conductivity and a predominantly capacitive response above 1 GHz. The over-riding factor in reduced conductance for smaller particles is the inter-grain contact resistance, which increases rapidly as particle size reduces.

THP2H-06	Vector Near-Field Measurement System Using an Electro-Optic Microcavity and Electrical Downconversion
1660	D. Lee¹, J. Kang², C. Chen¹, J. F. Whitaker¹, ¹University of Michigan, Ann Arbor, United States, ²Dong Seoul College, Seongnam, Republic of Korea
	An electro-optic (EO) field-mapping system that features a continuous-wave laser-diode optical source, an entirely fiber-coupled beam path, a resonance-assisted EO-microcavity probe, and an RF-downconversion mixing circuit is shown to be effective for extracting near-field vector RF information. The system is the first of its kind to allow amplitude and phase analysis of signals interrogated with a continuous optical beam and no polarization components in the EO-modulation section. A complete tangential-electric-field characterization in the near field of an RFID antenna – a small planar loop intended for applications in mobile-reader instruments – is presented, with a 35 dB signal-to-noise ratio attained.

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