Liangjin Xue

Compact microstrip lowpass filter based on defected ground structure and compensated microstrip line

An improved defected ground structure (DGS) with compensated microstrip line is investigated for low-pass filter (LPF) applications. With this structure, the basic resonant element exhibits the elliptic-function low-pass responses. The use of introduced resonant elements allows sharp cutoff frequency response and high harmonic suppressions together with small size to be obtained with less number of periodic structures. An equivalent lumped L-C circuit model is presented and its corresponding L-C parameters are also extracted by using parametric relationships. Based on the equivalent circuit model, a 3-pole LPF, using 3 DGS units cascaded, is optimally designed and implemented; measurements show good consistency with calculations.

Knowledge-Based Artificial Neural Network Models for Finline

Finline plays an important role in millimeter-wave integrated-circuit design. In this paper, a knowledge-based artifcial neural network is used to model the finline. Using prior knowledge input method and Bayesian regularization technique make the neural network models for finline reduce the amount of training data needed and prevent overfitting in neural network training. The neural network is electromagnetically developed with a set of training data that are produced by the fnite element method, which is robust both from the angle of time of computation and accuracy.

Design of a Novel Bandpass Filter in Millimeter-Wave Band

In this paper, a novel Bandpass Filter (BPF) combining microstrip parallel-coupled with end-coupled resonators is proposed. The filter not only allows the cross coupling to be realized but also makes itself compactness. At 35GHz, such a filter is designed and experimental results are discussed.

Knowledge-Based Artificial Neural Network Models for Microstrip Radial Stubs

Radial stubs are a superior choice over low characteristic impedance rectangular stubs in terms of providing an accurate localized zero-impedance reference point and maintaining a low input impedance value over a wide frequency range. In this paper, knowledge-based artificial neural networks are used to model the microstrip radial stubs. Using space-mapping technology and Huber optimization make the neural network models for radial stubs decrease the number of training data, improve generalization ability, and reduce the complexity of the neural network topology with respect to the classical neuromodeling approach. The neural networks are developed for design and optimization of radial stubs, which are robust both from the angle of time of computation and accuracy.

Dielectric resonator suspended on E-plane

An E-plane suspended dielectric resonator structure specially suitable for millimeter wave is suggested and analyzed in this paper. This structure is compatible with E-plane integrated circuits and can achieve much higher Q-factor than those of microstrip structure. This structure provides an approach for high Q-factor elements for E-plane integrated circuits, could enlarge their application field and improve their performance. A Ka band E-plane suspended dielectric resonator was designed and tested, which achieved a Q-factor of over 3000.

Analysis and design of SP4T switch

The analysis and design method of the SP4T switch using waveguide-tonikrostrip transition is presented on the basis of a new revised empirical expression in the critical region for the transition. General agreement between theoretical and experimental results confirms the validity of the method.

General approach for finding the characteristics of chiral layered media

In this paper, a systematic approach is presented for finding the resonant frequency, damping factor and EM field distribution of a layered planar structure consisting of chiral media and having arbitrary conductor sheets at the interfaces. The analysis is based on the spectral dyadic Greens function followed by a Ritz-Galerkins process, using matrix analysis in the Fourier transform spectral domain. The great value of our formulation lies in that it provides methodology for the solutions to chiral layered media problems.