Antenna Theory And Design

In general, Micropower Impulse Radar (MIR) depends on Ultra-Wideband (UWB) transmission systems. UWB technology can supply innovative new systems and products that have an obvious value for radar and communications uses. Important applications include bridge-deck inspection systems, ground penetrating radar, mine detection, and precise distance resolution for such things as liquid level measurement. Most of these UWB inspection and measurement methods have some unique qualities, which need to be pursued. Therefore, in considering changes to Part 15 the FCC needs to take into account the unique features of UWB technology. MIR is applicable to two general types of UWB systems: radar systems and communications systems. Currently LLNL and its licensees are focusing on radar or radar type systems. LLNL is evaluating MIR for specialized communication systems. MIR is a relatively low power technology. Therefore, MIR systems seem to have a low potential for causing harmful interference to other users of the spectrum since the transmitted signal is spread over a wide bandwidth, which results in a relatively low spectral power density.

/pdf/response-to-fcc-98-208-notice-of-inquiry-in-the-matter-of-3attixctl7.pdf

Response to FCC 98-208 notice of inquiry in the matter of revision of part 15 of the commission's rules regarding ultra-wideband transmission systems

Ultra Wideband Signals and Systems in Communication Engineering

소형 안테나 ( Small Antennas )

This paper addresses the problem of anisotropy in substrate materials for microwave integrated-circuit applications. It is shown that in modeling the circuit characteristics, a serious error is incurred which becomes larger with increasing frequency when the substrate anisotropy is neglected. Quasi-static, dynamic, and empirical methods employed to obtain the propagation characteristics of microstrip, coplanar waveguides, and slotlines on anisotropic substrates are presented. Numerical solutions such as the method of moments and the transmission-line matrix technique are outlined. The modified Wiener-Hopf, the Fourier series techniques, and the method of lines are also discussed. A critique of the aforementioned methods and suggestions for future research directions are presented. The paper includes new results as well as a review of established methods.

Integrated-Circuit Structures on Anisotropic Substrates

This paper discusses the design of a I-Q modulator using six port microwave network at a carrier frequency of 1.9 GHz which can support carrier leakage suppression and generate different digital modulations like WCDMA, QAM etc. Such modulator has simplicity in hardware realization, low cost and low power consumption. Measurement verifies modulation results with a 5 MHz WCDMA and 16 quadrature amplitude modulation signal generated at 10 mega symbol/s.

Modulator design using six port microwave network at a carrier frequency of 1.9 GHz

This paper presents a novel technique for tuning center frequency of substrate integrated waveguide (SIW) band pass filter (BPF), by loading simple dielectric rods of different dielectric materials on resonant cavities and coupling apertures. Tunability in center frequency of SIW BPF is first estimated with the help of full-wave 3D EM simulator and then verified experimentally. Tunability is achieved with variation in position, dimension and permittivity of dielectric rods. This initial investigation demonstrates a wide tuning capability of the proposed technique with an insertion loss less than 2dB and return loss greater than 10dB in X-band.

Tunable SIW Band Pass Filters

This paper presents a compact band notched ultra wideband (UWB) antenna with complementary split ring resonator (CSRR) for portable wireless communication. The total size of the antenna is 30×16×0.79 = 379.2 mm3. The proposed antenna is capable to attain high bandwidth starting from 2.8 to more than 11 GHz with notched band from 4.9 to 5.4 GHz. The characterization for radiation parameters, like return loss, surface current, radiation pattern, antenna gain and efficiency have been done experimentally and good agreement between simulated and measured results has been received.

Compact band-notched UWB antenna with CSRR for portable wireless communication

This paper presents daily activity recognition using wearable ultra-wideband technology. Channel parameters are analyzed for various postures occurring during the daily activity which act as key features to estimate the activity trend. Compact wearable antennas are placed on suitable locations on the human subject for each activity (walking, standing and sitting) studied in order to have maximum direct path propagation between the two wearable on-body nodes. It is observed that the three activities analyzed show distinct variation in the channel features making it possible to classify the activities through statistical analysis and inter-distance measurements between the wearable nodes. Low correlation is observed between the activity patterns with 0.01-0.3 correlation coefficient values. This indicates that the activities can be easily distinguished from each other using channel information. The work will be suitable for tracking, rehabilitation and activity monitoring applications in the healthcare domain.

Wearable Ultra Wideband Technology for Daily Activity Recognition

This work reports development of a fully integrated dual band low noise amplifier(LNA) in 0.18 μm CMOS at 2.8/3.4GHz for WLAN and Wi-MAX applications. Dual-band operation is achieved by switching one capacitor each in input and output matching networks. Measured results show a gain of 5 dB/7 dB at 2.8GHz/3.4GHz. Key features of the LNA are: high IIP3 > +1.5dBm (in both bands) while consuming 5.7mA from a 1.8V supply, a single control input and active area of 0.16mm2. An analytical expression for voltage gain has also been derived and verified in both bands.

Shiban K. Koul

Papers

Modulator design using six port microwave network at a carrier frequency of 1.9 GHz

Tunable SIW Band Pass Filters

Compact band-notched UWB antenna with CSRR for portable wireless communication

Wearable Ultra Wideband Technology for Daily Activity Recognition

Analysis and design of a fully integrated, linear dual band LNA for WLAN and Wi-MAX application