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A measurement method using the TM0m0 mode cylindrical cavity with a dielectric rod sample inserted on the center axis is proposed to measure the accurate complex permittivity (relative permittivity epsivr and loss tangent tandelta), which can be obtained by the rigorous electromagnetic field analysis on the basis of the Ritz-Galerkin method. The complex permittivity of a polyethylene rod sample is...
A miniaturized microstrip triplexer with a common resonator has been proposed in this paper. By exploiting the variable frequency response of stepped-impedance resonator, the common resonator can be shared by three filter channels of a triplexer if its fundamental and higher-order spurious resonant frequencies are properly assigned. The proposed triplexer with a third-order Chebyshev frequency response...
An effective evaluation method of complex permittivity in wide microwave frequency range is proposed by using rigorous calculation on partially filled materials in coaxial line. Electromagnetic field analysis for the evaluation is based on extended spectral domain approach combined with mode-matching method (ESDMM). ESDMM is accurate and more efficient than FEM, and suitable for the iterative fitting...
In this paper, a circularly polarized (CP) microstrip antenna with vertical ground for RFID (radio frequency identification) reader applications is presented. The proposed antenna is composed of a radiating patch on a substrate and a vertical ground surrounding four sides of the antenna. The vertical ground reduces the resonant frequency about 25% comparing to that without vertical ground. Relatively...
The microwave dielectric properties and the microstructures of Nd(Co1/2Ti1/2)O3 ceramics prepared by conventional solid-state route have been studied. It is found that low-level doping of B2O3 (up to 0.75 wt%) can significantly improve the density and dielectric properties of Nd(Co1/2Ti1/2)O3 ceramics. At 1320degC/4 h, Nd(Co1/2Ti1/2)O3 ceramics with 0.75 wt% B2O3 addition possesses a dielectric constant...
Two microstrip filters are diplexed at the input and output ports to realize a dual-band characteristic. The center frequencies, bandwidths and orders can be quite arbitrary since the two individual filters are realized independently. T- junctions are used to connect filters in parallel and extended microstrip arms are added to each filter for minimizing the mutual couplings at design frequencies...
This paper presents an ultra- wideband (UWB) resonator and a bandpass filter (BPF) consisting of quasi- lumped elements using a microstrip line (MSL). First of all, a resonator using a high-impedance inductive line and a gap capacitor is examined by an electromagnetic simulator. The simulated results of the resonator show UWB bandpass characteristics with two controllable stop- bands by adjusting...
Novel microstrip diplexer structures composed of a dual-passband filter together with two matching circuits are proposed. By using only a single dual-passband filter, the proposed diplexer may be made compact when compared with the conventional diplexer configuration which has two single- passband filters. In this study, the dual-passband filter is realized using the parallel-coupled microstrip structures,...
In wired data transmissions, a technique to increase the data rate is to transmit data in parallel cables. This paper describes a technique for wireless and parallel data transmissions to increase the data rate to above Gbps. In the proposed system each transceiver pair can handle a data rate of up to 6.17 Gbps per channel using well-proven modulation techniques. Each channel utilizes 11 sub-bands...
We present a spatially superposed Mary-quadrature amplitude modulation (QAM) communication system that can provide efficient use of frequency resources and transmitted power. The system incorporates multiple conventional quaternary phase shift key (QPSK) modulators and combines their output signals spatially with a specially tailored antenna array to produce an M-ary QAM signal. Thus, it can operate...
In this paper we show an edge-fed 4- port microstripline integrated antenna that has the dual function of power combining as well as being a radiator. The radiation pattern is similar to a two element microstrip half-wave patch array. The edge-feeding allows transistors of an amplifier to be connected directly to the antenna thereby eliminating interconnecting lines. The antenna provides ease of transistor...
In this paper, the two slot array antennas fed by integrated waveguide are proposed and designed on liquid crystal polymer to reduce the transmission loss of the feeding line and enable an easy integration. For 60 GHz wireless LAN applications, a high antenna gain is required to overcome the propagation loss. Also, we investigated fan beam antenna topology to maximize the azimuth coverage. Antenna...
The authors have been developing a wireless HDTV camera for TV studio use, which can transmit high picture-quality HDTV signals with short delay. A MIMO-OFDM transmission system that has two transmitting and four receiving antennas in the 55 GHz-band was proposed to ensure a reliable link and was named the "millimeter-wave mobile camera". Transmission experiments were conducted using a prototype...
A system designed to measure the space-time variation of rainfall rate R (mm/h) and specific attenuation Y (dB/km) is presented. The design constraints include a limited budget and a desired capability of capturing realistic propagation conditions expected to occur in millimeter-wave wireless systems with short links operating in a tropical region. The system consists of a disdrometer, a network of...
We developed a low-power and high- sensitivity cloud profiling radar transmitting frequency modulated continuous wave (FM-CW) at 95 GHz for ground-based observations. Using the developed millimeter-wave radar, we observed clouds on cruises on "Mirai", a Japanese scientific research vessel, in the Arctic Ocean and the southwest of the Pacific Ocean in 2004, and northern half of the Pacific...
A novel four-line, two-geometry (FLTG) measurement technique using coplanar waveguide structures is proposed for investigations on material characteristics from 1 GHz to 110 GHz. This measurement-based technique is simple and efficient when compared with other methods, and provides less uncertainty in the analysis, especially at mm-wave frequencies. The technique has been applied to the characterisation...
Dielectric properties of pseudo-epitaxial perovskite ferroelectric PZN-PMN-PT thin films deposited on lanthanum aluminate (LAO) substrates were characterized for microwave application. Dielectric constant, voltage tunability, and loss tangent of the thin films were determined via coplanar waveguides (CPWs) and interdigital capacitors (IDCs) structures. Scattering parameters were extracted through...
This paper describes a single-stage 26 W negative feedback power amplifier, covering the frequency range 200-500 MHz using a 6 mm gate width SiC lateral epitaxy MESFET. Typical results at 50 V drain bias for the whole band are, around 22 dB power gain, around 43 dBm output power, minimum power added efficiency at P1dB is 47% at 200 MHz and maximum 60% at 500 MHz and the IMD3 level at 10 dB back-off...
Anti-parallel diode pair mixers offer the benefit of intermodulation nulling without conversion nulls. However, the practicality of intermodulation nulling in improving mixer distortion performance is dictated by the trade-off between conversion loss and local oscillator drive power requirements. In systems where noise figure is not critical and availability of local oscillator drive power is at a...
This paper reports a high power 60 GHz push-push oscillator fabricated using 0.12 mum GaAs metamorphic high electron-mobility transistors (MHEMTs). The devices with a 0.12 mum gate-length exhibited good DC and RF characteristics such as a maximum drain current of 700 mA/mm, a peak gm of 660 mS/mm, an fT of 170 GHz, and an fMAX of more than 300 GHz. By combining two sub-oscillators having 6 x 50 mum...
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