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An accurate and broad-band method for hetero junction bipolar transistors (HBT) small-signal model parameters-extraction is presented in this paper. An equivalent circuit for the HBT under a forward bias condition is proposed for extraction of access resistance and parasitic inductance. This method differs from previous ones by extracting the equivalent circuit parameters without using special test structure or global numerical optimization techniques. The main advantage of this method is that a unique and physically meaningful set of intrinsic parameters is extracted from im pedance and admittance representation of the measuredS-parameters in the frequency range of 1–12 GHz under different bias conditions. The method yields a deviation of less than 5% between measured and modeledS-parameters.

An accurate and broad-band method for heterojuction bipolar transistors(HBT) small-signal model parameters is presented in this paper.This method differs from previous ones by extracting the equivalent-circuit parameters without using spec ial test structure or global numerical optimization techniques.The main advantag e of this method is that a unique and physically meaningful set of intrinsic par ameters is extracted from impedance and admittance representation of the measure d S-parameters in the frequency range of 0.5—12GHz under different bias conditi ons.An equivalent circuit for the HBT under a forward-bias condition is proposed for extraction of access resistance and parasitic inductance.The method yields a deviation of less then 5% between measured and modeled S-parameters.

The concept of the photonic bandgap(PBG) is extended to a novel architecture wh ich consists of two fractal PBG plates stacked up in the direction perpendicular to the plane of the substrate. This novel, dual-layer fractal PBG is presented here as the substrate for a microstrip line, and the resulting configuration builds a low-pass filter of wide stop-band. In the specific design, the dual-layer PBG includes two kinds of fractal PBGs with different periodicities in which one fractal PBG consists of a first-order Sierpinski carpet, and the other consists of third-order Sierpinski gasket. Simulated and measured transmission parameters in comparison with the corresponding two filters with monolayer PBG show that the filter with the proposed fractal PBG drastically enhances the width of the stop-band.