Multilayer Lowpass Filter Research Articles

Frequency-Domain Thermal Modeling of Power Modules Based on Heat Flow Spectrum Analysis

Many efforts have been devoted to describe the multi-timescale thermal dynamics of power modules and frequency-domain modeling is a relatively new approach. Unfortunately, only the frequency-domain response of thermal impedance has been studied in recent works, so the existing models can only describe the temperature behaviors of semiconductors. In the reality, it is not only the temperature of semiconductors which is important but also of other parts of the package. In this article, a novel perspective to study the thermal dynamics by analyzing heat flow behaviors is proposed. Frequency spectrum analysis in finite-element method simulation has been first used in this article, and it reveals that heat flow of the power semiconductor device behaves as a multi-layer low-pass filter (LPF). As a result, a novel modelling method of heat flow with a 7order-3frequencies LPF has been developed in this article and it can provide a comprehensive description of heat flow behaviors for power modules at full bandwidth. Meanwhile, the effects on heat flow behaviors brought by boundary conditions are also considered to ensure that the proposed model can be easily adapted to different boundary conditions. The effectiveness and accuracy of the proposed model has been verified by both simulations and experiments.

A simple transformation from lowpass to bandpass filter using a new quasi‐arrow head defected ground structure resonator and gap‐J‐inverter

ABSTRACTIn this article, a new compact quasi‐arrow head defected ground structure (DGS) lowpass filter (LPF) is proposed. The proposed DGS behaves as a resonant element which allows size compactness and harmonic suppression in the rejection band. The proposed LPF presents the advantages of compactness, low insertion loss, and ultrawide stopband with 20 dB attenuation from 6 GHz to >20 GHz. The length of the proposed multilayer LPF is reduced to 0.143 λg at 3 GHz in comparison with 0.2 λg for the cascaded topology with λg = 0.157 m. A novel compact bandpass filter (BPF) is presented by utilizing a simple transformation from LPF based on J‐inverter technique. The proposed BPF has low insertion loss and compact size. Finally, the simulated and experimental results of proposed structure are found to be in good agreement with the simulation results. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:947–953, 2016

Design of ultra‐wide stop‐band DGS low‐pass filter using meander‐ and multilayer‐techniques

AbstractThis article presents a new dog‐bone defected ground structure (DGS) for low‐pass filter (LPF) applications with wide‐rejection band and low‐insertion loss in the pass‐band region.The prototype LPF consists of three dog‐bone cells in the ground plane with an open stub on the top layer acting as a compensated capacitor. The prototype LPF is then realized as a multilayer structure to enhance the filter response and reduce its size. The size reduction of the proposed multilayer LPF is about 34% more than the conventional one. The proposed filter has been fabricated and measured. Good agreement can be realized between the electromagnetic simulation and the measurement results. To minimize the difference between the simulation and measurement results, and at the same time to reduce the loss in the pass‐band region, a modification to the topology of the structure with the aid of the meander idea is used. The meander‐filter presents advantages of compactness, low insertion loss, and high out‐band suppression. The dog‐bone DGS cell is then used as a photonic band gap structure to minimize the coupling between two probe‐fed patch antennas and to improve the two antenna element array efficiency. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1276–1281, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27541

Design of compact microstrip filter with large reject band using a new multisectioned T‐shaped defected ground structure and multilayer technique

AbstractIn this article, a new compact defected ground structure (DGS) low pass filter (LPF) with wide rejection band, low insertion loss in the stopband, and sharp transition from passband to stopband is proposed. The prototype LPF is composed of three repetitive DGS elements with open stubs to act as a compensated capacitance. Each single DGS element consists of multisections of T‐shaped slots. The filter is then realized as a multilayer structure to achieve size reduction and enhance the filter response. The proposed filter has been fabricated and measured. The agreement between the simulated and measured results confirms the effectiveness of the proposed concept. Finally, multilayer LPF is transformed to band pass filter using J‐inverter method. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26157