Wen-Jeng Lin

Investigation in Open Circuited Metal Lines Embedded in Defected Ground Structure and Its Applications to UWB Filters

A novel method for notch implementation in ultrawideband (UWB) bandpass filter (BPF) using open circuited metal lines embedded in a defected ground structure (DGS) is proposed. Distinct from traditional notch implementation, the proposed method uses the additional metal lines with half waveguide length embedded in defected ground structure to produce additional notch band behavior based on the DGS bandpass behavior. Furthermore, the equivalent circuit model of the proposed UWB BPF with notch implementation is established for explaining the circuit behaviors more explicitly. In this way, the proposed circuit has a very small size, only amounting to 0.41 by 0.22 guided wavelength at the center frequency of 6.85 GHz. The experimental filter has a notch band frequency of 5.5 GHz, with two observable attenuation poles at 1.65 and 11.36 GHz, respectively. The measured BPF insertion loss is less than 1.0 dB throughout the passband of 3.1 to 10.6 GHz, and the variation of group delay is less than 0.2 ns in this band, except for the notched band.

A New Approach of Dual-Band Filters by Stepped Impedance Simplified Cascaded Quadruplet Resonators with Slot Coupling

This paper presents novel approaches for dual-band bandpass fllter design utilizing stepped impedance simplifled cascaded quadruplet resonators (SI-SCQRs) with slot coupling. A pair of SI- SCQRs forms a cross coupled dual-band flltering path to provide high selectivity passband response, and a slot coupling structure provides SI-SCQRs with another flltering path for improving and controlling the performances of the dual-band fllter such as insertion loss and bandwidth. Measured insertion losses are 0.26dB and 1.2dB, and return losses are better than 16.3dB and 15.2dB at the flrst and second

A Low Power Consumption and Wide-Band Input Matching CMOS Active Balun for UWB System Applications

This work presents an ultra-wideband (UWB) active balun (balanced-to-unbalanced) with current-reused technique for wideband input matching and low power consumption by using standard 0.18 μm CMOS processes. The proposed circuit, using parallel common gate and common source structure, can efficiently improve the input-matching bandwidth for up to 10 GHz. Besides, the proposed circuit has good gain imbalance and phase imbalance from 3.1 GHz to 10.6 GHz. The proposed active balun achieved 4 ± 1 dB gain with amplitude (gain) imbalances less than 0.5 dB, phase differences of 180° ± 2°, 11.7 mW power consumption at 1.8 V supply voltage from 3.1 GHz to 10.6 GHz, and the chip size including pads is 0.76 × 0.73 mm2.

Miniaturized Wideband Ring-Type Bandpass Filters with Upper Stopband Characteristic

A new class of wideband ring-type microstrip bandpass filter is proposed under smaller size of three quarters waveguide length section. One via hole is placed at perpendicular position in a squared ring, whereas two short-circuited sections are formed in the ring-type microstrip bandpass filter similar to a dual-mode ring filter in shape, thereby making up a three quarters waveguide length ring-type microstrip bandpass filter. By adjusting the short-circuited sections, the bandwidth of the center frequency can be controlled easily. As a pair of open-circuited stubs is placed between the two ports, two extra resonances can be used to improve the out-of-band performance. Afterwards, a novel microwave microstrip filter has been successfully fabricated with the lower insertion loss S 21 of 0.48 dB, return loss S 11 of 30 dB, 3 dB bandwidth of 80%, and central frequency of 2.4 GHz. Simulated and measured results show good wideband filtering performance with widened upper stopband outside the wide passband.

Controlling the Frequency of Simultaneous Switching Noise Suppression by Using Embedded Dielectric Resonators in High-Impedance Surface Structure

This work presents a novel design for high-impedance surface (HIS) embedded dielectric resonator (DR) structures to e-ciently control bandwidth of suppression simultaneous switching noise (SSN) in high speed digital printed circuit boards (PCBs). The proposed structure is designed by periodically embedding high dielectric constant materials into the substrate between a continuous power plane and a middle patch. A conventional HIS structure has only one resonance frequency to produce stopband while the proposed structure has two resonances to widen the suppression bandwidth. The i30dB stopband of the proposed structure is about two times wider than that of a conventional HIS structure. The excellent SSN suppression behavior was verifled by measurements and simulations.

Simultaneous Switching Noise Suppression Using Nickel-Ferrite Thin Films

In this article, magnetic materials are employed to eliminate the ground bounce noise or simultaneous switching noise in high-speed digital circuits. The nickel film, deposited on a sapphire substrate by RF-sputter, was applied to suppress simultaneous switching noise. The proposed structure can efficiently restrain the simultaneous switching noise with broadband (totally 16GHz), and the ground bounce noise can be significantly lessened over 90%. Besides, the proposed structure does not produce undesired resonant peaks in the lower frequencies, and the electromagnetic interference problems are solved.

Multi-Suppression of Microstrip Bandpass Filter Using Split-Mode Excitations

A novel method for spurious suppression in bandpass filter using Split-Mode Excitations (SME) is proposed. Distinct from traditional ways for spurious suppression, the proposed method uses different excitations for six-order quarter-wavelength resonators to obtain good out-of-band performance. According to the split-mode, the proposed bandpass filter with wideband spurious suppression was designed by using three effective excitations to produce three spurious conditions. In this way, the proposed circuit has a very small size, only amounting to 0.08 by 0.32 guided wavelength at the center frequency of 2.4 GHz. The out-of-band performance is improved easily and effectively with a rejection level better than 20 dB at least up to 20 GHz and done without using any cascaded circuits.

A Miniaturized Bandpass Filter with Controllable Harmonic by Using Split Impedance Resonators

In this paper, a miniaturized bandpass filter with controllable harmonic by using split impedance resonators is proposed. The proposed split impedance resonator is based on the theories of the basic parallel impedance formula and stepped impedance resonators (SIRs). In this way, the split impedance resonator can be effectively designed to obtain good coupling for reducing the insertion loss. Furthermore, a miniaturized bandpass filter with controllable spurious frequency is proposed. The proposed bandpass filter not only has good passband characteristics but also obtains miniaturization around 21.87% versus the traditional SIR bandpass filters.