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This paper presents a new microstrip open loop resonator bandpass filter (BPF) for wireless local area networks (WLAN) with wide stopband response. The proposed BPF is composed of a pair of half-wavelength open loop resonators and two additional resonators operating at the center frequency of 2.44 GHz. Two novel resonators consisted of asymmetrical spurlines and quarter-wavelength open-circuited stubs...
A novel wide stopband coplanar waveguide (CPW) low pass filter (LPF) using quarter wavelength stepped impedance resonators (SIR) is presented. The bandstop characteristics of the quarter wavelength short circuited stubs SIR are demonstrated. By cascading three tapered quarter wavelength short circuited stubs SIR and a CPW spurline resonator, the fabricated low pass filter has sharp rejection with...
This paper presents a novel branch-line coupler which has a wide stopband characteristic with attenuation 30 dB from 4 GHz to 8 GHz using defected ground structure (DGS). The conventional branch-line coupler suffers from the presence of spurious response at odd harmonics of the operating frequency. The proposed coupler adopts the two symmetrical dumbbell DGS under the input and output feed lines to...
In this paper, a novel compact planar three-way dual-band power divider using defected ground structure (DGS) is proposed. Based on this method, the power divider is reduced half of its original size. And it achieves a good performance. To verify the validity, a 915/2400 MHz power divider is fabricated, which could be applied in radio frequency identification (RFID) system. The experimental results...
A compact ultra-wideband (UWB) bandpass filter (BPF) is implemented with stepped impedance resonators (SIR) and T-shaped line. Fractional bandwidth (FBW) of the UWB BPF can be adjusted properly by changing the impedance ratio of the SIR. A transmission zero is created by the central open stub of the T-shaped line to suppress the second harmonic of the filter. In addition, the filter size is further...
In this paper, a novel empirical model based on Angelov model for SiC MESFETs with self-heating effect is presented. Modifications of drain current and nonlinear capacitive model are proposed to adapt to the measured date without the thermal subcircuit. These new models could simplify the equivalent circuit topology and are easier to implement in CAD simulation tools. A good agreement has been obtained...
The improvement of linearity and efficiency of power amplifier becomes the research focus in the wireless communication. Lots of new methods are proposed successively to realize high linearity and high efficiency, but most of them are implemented with active style and it is complex to implement. The defected ground structure (DGS) in transmission line can form frequency cutoff feature on a specific...
This paper presents the design and realization of a Ka band subharmonically pumped mixer using self-fabricated Schottky diodes. First, the design and fabrication of GaAs Schottky diode with the cutoff frequency of 650 GHz was introduced. Then the mixer's design was presented which consists of two parts: design of the passive linear part and optimization of the total mixer. Finally, the fabricated...
A new type of microstrip dual-mode microstrip filter using spurlines and L-shape slot is proposed in this letter. It is found interestingly that the embedded spurlines and slot can excite, couple and split the degenerate modes. Moreover, the transmission characteristics of the loop resonator can be controlled by adjusting the length of the embedded L-shaped slot appropriately. Parameter study of the...
The total isotropic sensitivity (TIS) is one of important parameters of the mobile phone, and should be measured by developers and manufacturers. But measuring TIS would take a long time based on the stepping test technique of the Cellular Telecommunications & Internet Association (CTIA). The paper proposed an efficiency measurement method for TIS based on data predication. As the relationship...
A microstrip wide slot antenna with a notched frequency band is proposed. The antenna is with an E-shaped radiation patch and is fed by microstrip line, and to realize the band notching function, an E-shaped slot is cut in the E-shaped radiation patch. The Finite Difference Time Domain method is used in the analysis and the results of the FDTD are essentially in agreement with the experimental results...
Using HFCS-I and MAFIA, a cubic resonator and a typical helical slow-wave structure are simulated and the quality factor of the cubic resonator and the attenuation constant of the helical slow-wave structure are stressed. The results from HFCS-I and MAFIA simulation are compared in detail and they are found to be in quite agreement. Therefore, the capability of HFCS-I on calculation of high-frequency...
Since the method of using GTEM cell to do EMI measurement is put forward, it gradually received the testers' attention because of the advantages of GTEM cell. In this paper, HFSS software is used to simulate a GTEM cell of classic structure, and the reliability of simulation is conformed from two aspects. The two aspects are characteristic impedance and output power of GTEM cell. The experiment result...
A weakly conditionally stable (WCS) finite-different time-domain (FDTD) algorithm is presented for resonant cavity analysis. The time-step in the WCS-FDTD is based on the largest cell size. And compared with the alternating-direction implicit (ADI) FDTD, the WCS-FDTD method is of higher accuracy and efficiency. Numerical results indicate that the CPU time for the WCS-FDTD method can reduced to about...
In this paper, a compact ultra-wideband (UWB) band-pass filter (BPF) with two steep rejected notch-bands is proposed. The designed UWB BPF is realized by cascading two interdigital hairpin resonator units with asymmetric open loading stubs and a spiral slot on microstrip line. The asymmetric loading stubs and spiral slot are studied and adopted to introduce notched bands. The lengths and the widths...
A kind of hollow copper waveguide is demonstrated for THz wave, it is namely a simple copper tube. THz Time-domain Spectroscopy system (TDS) is used to measure the character of the waveguide. The experimental result shows that it can be used to transmit the THz wave with high coupling efficiency, low attenuation and low dispersion. A lowest attenuation of 0.0046dB/mm at 0.557 THz is obtained for a...
An improved multiple mode resonant (MMR) ultrawideband (UWB) bandpass filter is proposed using a novel rectangular slit compact microstrip resonant cell (CMRC). The CMRC is formed by perforating on the central section of the MMR, which make the both structures incorporate into one successfully. Combining the CMRC lowpass filter and slow wave characteristics, the filter has widened stopband characteristic...
A normalized RC-FDTD algorithm is applied to study both the bistatic and monostatic radar scattering of perfectly conducting sphere covered with inhomogeneous unmagnetized plasma. The effects of electron density distributions and plasma collision frequencies on the radar cross section (RCS) are discussed respectively. The simulations confirm that plasma cladding can be successfully used to reduce...
Ultra-wide spectrum (UWS) pulser, in which avalanche transistor is used as its switch, can generate high-repetition and -stability short-pulse, but its power is sharply lower than that of SOS and Tesla generators. Marx circuit is used to increase the power of this type of pulser. Different charged-capacitance and class of Marx circuit determines different waveform and peak-power of output pulse. 20-class...
The complex gain baseband adaptive predistorter is flexible and practical. However, it's quite sensitive to errors in the linearization system. This paper analyzes and simulates the effect of errors in feedback path on linearization performance, and presents the protective considerations in algorithm design to ensure the convergence of the adaptation. The simulation results demonstrate that protection...
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