Papers by Keyword: Dual-Band

Abstract: This paper describes multi-band low noise amplifiers (LNAs) utilizing input matching transformers. We investigate a conventional dual-band LNA circuit utilizing a transformer, and show our analysis and simulation results for its circuit. Based on this, we propose a triple band LNA with transformers. We have calculated characteristics of the dual-band and triple-band LNAs. As the results, the LNAs show gain of 20dB while maintaining good input matching, in the frequencies at 2.59GHz, 3.50GHz and 5.41 GHz. Then we discuss configuration and design of coupling coefficients of the transformers.

Abstract: A novel coupled-line structure is proposed to design dual-band and high-power Gysel power dividers. Based on traditional even-and odd-mode technique, the analytical design theory is given and the electrical parameters analysis is provided. Four numerical examples are presented to demonstrate the flexible dual-band applications. A practical power divider operating at 1GHz and 2 GHz is designed. The calculated and full-wave simulated results verify our proposed idea.

Abstract: A novel coupled-line circuit configuration is proposed to design small-size dual-band Wilkinson power dividers. This proposed power divider consists of three sections of coupled lines and two isolation resistors. The analytical design theory is given and the electrical parameters analysis is provided. Six numerical examples are presented to demonstrate the flexible dual-band applications. To avoid a negative isolation resistor, a practical power divider operating at 1GHz and 2.2GHz with two positive-value resistors is designed. The calculated and full-wave simulated results verify our proposed idea. Keywords: Coupled-line, dual-band, power divider.

Abstract: A folded dual-band monopole antenna for 2.45 GHz and 5.8 GHz RFID tag applications is proposed in the present paper. It is formed by two folded monopole antennas for reducing the geometric size of the tag. One of them operates at 2.45 GHz, and the other operates at 5.8 GHz. The input impedance of the proposed antenna is designed to be conjugate matched to the chip impedance for the maximum power transfer. This antenna is modeled, analyzed, and optimized by HFSS. The simulation results demonstrate that the performances of the proposed antenna can satisfy the requirements of RFID system. The characteristics of the proposed antenna are simple structure, low cost, and small sizes.

Abstract: An imaging model of spatial point target in dual-band infrared was set up on the basis of Plancks law. The formation mechanism of differences of point target imaging characteristics in dual-and infrared was revealed. The impact of the target temperature, surface emission, transmission distance and the rate of detector response were analyzed in detail. This paper provides the basis for space target recognition.

Abstract: In this paper, two types of miniaturized dual-mode bandpass filters (BPF), a single-ring (SR) resonator, and a double-ring (DR) resonator are developed. By applying the capacitive-coupling technique to a dual-mode ring filter, a technique is proposed to miniaturize the dual-mode double-ring filter. An adjustable dual-band bandpass filter is achieved by developing a ring resonator where the two modes are capacitively coupled. Control of the filter center frequency is determined by the diameter of the ring and by the rings annular width. Filter coupling amount can also be adjusted by disturbance (perturbation) of an open stub attached to the annular disc. Proposed filters explore both single- and double-ring architectures. A single-ring resonator acting as a dual bandpass filter to allow 3.8 GHz and 7.8 GHz single is developed. A double-ring resonator to allow 2.05 GHz and 3.9 GHz signals is also developed. The ring resonators are fabricated on RO-4003 substrate, with relative dielectric constant of 3.38, thickness of 0.8 mm, and dielectric loss tangent of 0.0025. Results indicate the filters can be applied in the communications field.

Abstract: This study proposes a circuit structure with reconfigurable multiple bands bandpass filter. This circuit can provide a triple-band or dual-band bandpass facility by adjusting two open stubs (L6 and L7) location. The circuit design used three sections of transmission line in series, the two sets of the coupled lines connected to the gap in each transmission line, and two open stubs in the appropriate locations. The design and manufacturing of the circuit structure is innovative and simple. The center frequencies of the triple-band bandpass filter are set at 2.4, 4.2, and 6.5 GHz, respectively, while the center frequencies of the dual-band bandpass filter are the two lower pass band of the triple-band bandpass filter at 2.4 and 4.2GHz. The filters were simulated using the full-wave electromagnetic simulator, IE3D, and measured by Anritsu-37269D. The simulated and measured results show good agreement in the frequency of interest.

Abstract: This paper studies a very simple structure for dual-band bandpass filter. Filter is composed of two asymmetric coupled resonator circuit by two sets of different size stepped impedance resonator. This circuit applied microstrip line, coupling principle and impedance ratio by controlling the stepped impedance resonator to control the center frequency 2.6/5.2 GHz of the first and the second bandpass filter. The basic structure of the filter is constituted by the three sections of transmission line and two sets of SIR, that is, in two gaps of the three sections of transmission line parallel connection the equivalent inductances and capacitor of the two sets of SIR in series with the resonant circuit (LCL) to constitute bandpass filter. The low frequency 2.6 GHz is through the upper half of low impedance SIR, and the high frequency 5.2 GHz is through the lower half of high impedance SIR. This paper presents the design of asymmetric SIR-based dual-band bandpass filter, the filter structure is simple, easy to produce and can control the characteristics of the passband center frequency. By electromagnet simulation software( IE3D ) to simulate, the actual production of the circuit using a vector analyzer measurement, simulation and measurement results show good consistency.

Abstract: A two-way symmetrical modified Wilkinson power divider with shifted output ports and wide range frequency-ratio is proposed for dual-band application. The symmetrical Wilkinson power divider consists of one section coupled line, one section microstrip line, the shifting of two output ports to the middle, two open stubs at the input port and an isolation resistor. The corresponding nonlinear design equations are derived by using the even- and odd-mode analysis. Moreover, solving the nonlinear design equations by optimization algorithms, accurate numerical design parameters along with different frequency ratios are obtained. Finally, the proposed structure and design method are validated by simulation and experimental results of microstrip planar Wilkinson power divider.

Abstract: A printed ring-shaped monopole antenna fed by coplanar waveguide for use in the dual-band wireless communication system has been presented and investigated. By adding some branch strips inside the ring and changing its size, as well as the further optimization, the proposed antenna could work effectively within the scope of 2.4-2.484GHz and 5.15-5.825GHz frequency band. Practical antenna structure is fabricated. The details of the antenna design and both the theoretical and experimental results are discussed.