Fully Distributed Tunable Bandpass Filter Based on Ba0.5Sr0.5TiO3 Thin-Film Slow-Wave Structure

This paper presents simulation and measurement results of fully distributed tunable coplanar bandpass filters (BPFs) with center frequencies around 6 GHz that make use of ferroelectric Barium Strontium Titanate (BaxSr1−xTiO3 or BST-x) thin film as tunable material. The two experimental bandpass filters tested are based on a novel frequency-agile structure composed of cascaded half wavelength slow-wave resonators (2 poles) and three coupled interdigital capacitors (IDCs) optimized for bias voltage application. Devices with gap dimensions of 10 and 3 μm are designed and fabricated with a two-step process on polycrystalline Ba0.5Sr0.5TiO3 thin films deposited on alumina substrate. A frequency tunability of 9% is obtained for the 10 μm gap structure at ±30 V with 7 dB insertion loss (the BST dielectric tunability being 26% with 0.04 loss tangent for this gap size). When the structure gap is reduced to 3 μm the center frequency shifts with a constant 9 dB insertion loss from 6.95 GHz at 0 V to 9.05 GHz at ±30 V, thus yielding a filter tunability of 30% (the BST dielectric tunability being 60% with 0.04 loss tangent for this gap size), a performance comparable to some extent to localized or lumped element BPFs operating at microwave frequency (>2 GHz).

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Inverse Design of a Microstrip Meander Line Slow Wave Structure with XGBoost and Neural Network

Electronics ◽

10.3390/electronics10192430 ◽

2021 ◽

Vol 10 (19) ◽

pp. 2430

Author(s):

Yijun Zhu ◽

Yang Xie ◽

Ningfeng Bai ◽

Xiaohan Sun

Keyword(s):

Neural Network ◽

Slow Wave ◽

Mean Squared Error ◽

Transmission Rate ◽

Wave Structure ◽

Cold Test ◽

Slow Wave Structure ◽

Center Frequency ◽

Particle In Cell ◽

Meander Line

We present a new machine learning (ML) deep learning (DL) synthesis algorithm for the design of a microstrip meander line (MML) slow wave structure (SWS). Exact numerical simulation data are used in the training of our network as a form of supervised learning. The learning results show that the training mean squared error is as low as 5.23 × 10−2 when using 900 sets of data. When the desired performance is reached, workable geometry parameters can be obtained by this algorithm. A D-band MML SWS with 20 GHz bandwidth at 160 GHz center frequency is then designed using the auto-design neural network (ADNN). A cold test shows that its phase velocity varies by 0.005c, and the transmission rate of a 50-period SWS is greater than -5 dB with the reflectivity below −15 dB when the frequency is from 150 to 170 GHz. Particle-in-cell (PIC) simulation also illustrates that a maximum power of 3.2 W is reached at 160 GHz with 34.66 dB gain and output power greater than 1 W from 152 to 168 GHz.

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Thin Film Lithium Niobate Electro-optic Modulator Based on a Slow Wave Structure

14th Pacific Rim Conference on Lasers and Electro-Optics (CLEO PR 2020) ◽

10.1364/cleopr.2020.c4c_3 ◽

2020 ◽

Author(s):

Xuecheng Liu ◽

Bing Xiong ◽

Changzheng Sun ◽

Zhibiao Hao ◽

Lai Wang ◽

...

Keyword(s):

Thin Film ◽

Lithium Niobate ◽

Slow Wave ◽

Wave Structure ◽

Slow Wave Structure ◽

Electro Optic ◽

Electro Optic Modulator

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Study of insertion loss for a Ka-band meander line slow-wave structure

2018 IEEE International Vacuum Electronics Conference (IVEC) ◽

10.1109/ivec.2018.8391583 ◽

2018 ◽

Author(s):

Wang Shaomeng ◽

Sheel Aditya

Keyword(s):

Slow Wave ◽

Insertion Loss ◽

Wave Structure ◽

Slow Wave Structure ◽

Ka Band ◽

Meander Line

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Design of a Suspended Stripline Narrow Bandpass Filter with Ultrawideband Harmonic Suppression

International Journal of Antennas and Propagation ◽

10.1155/2018/9029240 ◽

2018 ◽

Vol 2018 ◽

pp. 1-6

Author(s):

Ju Seong Park ◽

Wahab Mohyuddin ◽

Hyun Chul Choi ◽

Kang Wook Kim

Keyword(s):

Insertion Loss ◽

High Performance ◽

Bandpass Filter ◽

Design Method ◽

Characteristic Impedance ◽

Wireless Systems ◽

Bandpass Filters ◽

Center Frequency ◽

Harmonic Suppression ◽

Low Loss

A design method of narrow bandpass filters (NBPFs) of 4–6% bandwidth with ultrawideband suppression of harmonic passbands, utilizing two cascaded step impedance resonators (SIRs) in a suspended stripline, is proposed in this paper. The proposed design utilized the characteristics of a suspended stripline, which provides a much higher characteristic impedance ratio as compared with that of the microstripline, enabling ultrawideband harmonic suppression. As an example of the NBPF, a filter with a passband center frequency f0 of 0.75 GHz and bandwidth of 5% was implemented and proved to suppress the harmonic passbands up to 13.5 f0. Since the proposed filter was implemented on the suspended stripline, the passband insertion loss was only −0.9 dB, which is low as compared with other previous designs. The proposed filter is a compact high-performance low-loss NBPF, which can be applicable to various wireless systems.

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Integrated Monolithic Crystal Filter for Citizen Band Transceivers

ElectroComponent Science and Technology ◽

10.1155/apec.8.53 ◽

1981 ◽

Vol 8 (1-2) ◽

pp. 53-59

Author(s):

Masaaki Ono ◽

Shigeo Tanji ◽

Hideki Tominaga

Keyword(s):

Thin Film ◽

Low Temperature ◽

Insertion Loss ◽

Mass Production ◽

Center Frequency ◽

Mechanical Shock ◽

Dual Mode ◽

Fine Grain ◽

Narrow Bandwidth ◽

Shock Resistance

This paper will describe a SSB 10.7 MHz IF filter for CB band transceivers employing an integrated capacitor circuit and four dual mode Monolithic Crystal Filters (MCFs) of AT cut Quartz. With a narrow bandwidth of 2 × 10−4, an insertion loss of less than 5 dB, and a low temperature coefficient of the center frequency of within ± 20 ppm over the range of − 35 to + 65℃, this filter also meets mechanical shock-resistance requirements. The integrated capacitor circuit consists of thin film Ta2O5capacitors and interdigital gap capacitors formed on both sides of a Fine Grain Alumina (FGA) substrate. Four MCFs are directly soldered to the substrate of the integrated capacitor circuit, allowing this filter to be made smaller and lighter and have better resistance to mechanical shock. Also important, the manufacturing process is suitable for mass production.

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