Liquid crystal dual-mode band-pass filter with improved performance

2015 ◽  
Vol 23 (2) ◽  
Author(s):  
J. Torrecilla ◽  
C. Marcos ◽  
V. Urruchi ◽  
J.M. Sánchez-Pena ◽  
O. Chojnowska

AbstractOver the last twenty years, there has been a growing interest in the design of tunable devices at microwave frequencies by us- ing liquid crystals technology. In particular, the use of liquid crystals with high dielectric anisotropy allows manufacturing voltage-controlled devices to operate in a wide frequency range. In this work the frequency response of a liquid crystal band-pass filter with dual-mode microstrip structure has been studied in depth by using a simulation software tool. A reshap- ing of a conventional dual-mode square patch resonator bandpass filter with a square notch, studied in the literature, has been proposed with the goal of improving the filter performance. The main features achieved are a significant increase in the return loss of the filter and a narrowing of a 3-dB bandwidth. Specifically, a reduction in the filter bandwidth from 800 MHz to 600 MHz, which leads to a return loss increase from 6 dB to 12.5 dB, has been achieved. The filter centre frequency can be tuned from 4.54 GHz to 5.19 GHz.

Frequenz ◽  
2017 ◽  
Vol 71 (7-8) ◽  
Author(s):  
Weiping Cao ◽  
Di Jiang ◽  
Yupeng Liu ◽  
Yuanwang Yang ◽  
Baichuan Gan

AbstractIn this paper, a novel microwave continuously tunable band-pass filter, based on nematic liquid crystals (LCs), is proposed. It uses liquid crystal (LC) as the electro-optic material to mainly realize frequency shift at microwave band by changing the dielectric anisotropy, when applying the bias voltage. According to simulation results, it achieves 840 MHz offset. Comparing to the existing tunable filter, it has many advantages, such as continuously tunable, miniaturization, low processing costs, low tuning voltage, etc. Thus, it has shown great potentials in frequency domain and practical applications in modern communication.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Yupeng Liu ◽  
Di Jiang ◽  
Lei Xia ◽  
Ruimin Xu

This paper proposes a novel microwave continuous adjustable band-pass filter integrated power divider based on nematic liquid crystals (LCs). The proposed power divider uses liquid crystal (LC) as the dielectric material. It can realize phase shift by changing the dielectric anisotropy, when biasing the high anisotropy nematic liquid crystal. It is mainly used in microwave frequencies. It has a large number of advantages compared to conventional filter integrated power divider, such as low loss, multifunction integration, continuous adjustable, miniaturization, low processing costs, low operating voltage, high phase shift, and convenient manufacture. Therefore, it has shown great potential for application.


2015 ◽  
Vol 789-790 ◽  
pp. 511-514
Author(s):  
Zhi Gang Wang ◽  
Hao Ding

In this paper, a W-band dual-mode substrate integrated cavity fourth-order band-pass filter is presented, which utilizes LTCC technology. The filter is composed of two dual-mode resonators which are constructed by rows of via arrays in the substrate layer. Two coupling vias near particular diagonal corners are set to perturb the two degenerate modes in each cavity and thus to generate an intra-cavity coupling. The filter exhibits 3dB bandwidth about 2.4GHz, return loss better than 19dB and out of band rejection better than 30dB. The filter occupies the area of 3.752mm4.064mm (including the two feeding lines) in the LTCC substrate.


2018 ◽  
Vol 54 (25) ◽  
pp. 1444-1446
Author(s):  
Jianfei Chen ◽  
Sheng Zhang ◽  
Chao Zhang ◽  
Yuehua Li

2021 ◽  
Vol 21 (1) ◽  
pp. 1
Author(s):  
Arie Setiawan ◽  
Taufiqqurrachman Taufiqqurrachman ◽  
Adam Kusumah Firdaus ◽  
Fajri Darwis ◽  
Aminuddin Rizal ◽  
...  

Short range radar (SRR) uses the K-band frequency range in its application. The radar requires high-resolution, so the applied frequency is 1 GHz wide. The filter is one of the devices used to ensure only a predetermined frequency is received by the radar system. This device must have a wide operating bandwidth to meet the specification of the radar. In this paper, a band pass filter (BPF) is proposed. It is designed and fabricated on RO4003C substrate using the substrate integrated waveguide (SIW) technique, results in a wide bandwidth at the K-band frequency that centered at 24 GHz. Besides the bandwidth analysis, the analysis of the insertion loss, the return loss, and the dimension are also reported. The simulated results of the bandpass filter are: VSWR of 1.0308, a return loss of -36.9344 dB, and an insertion loss of -0.6695 dB. The measurement results show that the design obtains a VSWR of 2.067, a return loss of -8.136 dB, and an insertion loss of -4.316  dB. While, it is obtained that the bandwidth is reduced by about 50% compared with the simulation. The result differences between simulation and measurement are mainly due to the imperfect fabrication process.


2014 ◽  
Vol 7 (6) ◽  
pp. 655-660 ◽  
Author(s):  
Photos Vryonides ◽  
Symeon Nikolaou ◽  
Sangkil Kim ◽  
Manos M. Tentzeris

A reconfigurable band-pass filter with switchable bandwidth, for wireless applications is demonstrated using a dual-mode microstrip square-loop resonator. The proposed filter has been designed on Rogers RO4003C and achieves switchable bandwidth by changing the length of two tuning stubs with the implementation of two strategically placed p-i-n diodes as switching elements. The filter was designed with a center frequency of 2.4 GHz and the two distinct operation states have bandwidths, 113 MHz (4.8%) with an insertion loss of 1.2 dB and 35 MHz (1.5%) with an insertion loss of 1.5 dB. The physical size of the fabricated reconfigurable filter including the implementation of the DC bias lines is comparable to the size of a conventional filter.


Photonics ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 41 ◽  
Author(s):  
Vishwanath Mittapalli ◽  
Habibulla Khan

This article describes the analysis and design of the excitation schemes of the plasmonic angular ring resonator-based band-pass filters using a metal-insulator-metal (MIM) waveguide. The excitation schemes of the plasmonic angular ring resonator-based band-pass filters have been analyzed in terms of their physical length by using commercially available electromagnetic full-wave simulation software (CST microwave studio). The excitation schemes of the plasmonic angular ring resonator-based band-pass filter using a MIM waveguide have been realized at the optical O (1260–1360 nm) and U (1625–1675 nm) bands, respectively, as it has dual-band characteristics. The excitation schemes of the plasmonic angular ring resonators have been designed and simulated to determine the variation in transmission and reflection coefficients. The magnetic field distribution of the proposed filters was observed. The ring resonators require low power and had a compact size, which was further used for the development of photonic integrated circuits (PICs). The applications of these resonators are further extended and they are used in the development of antennas, branch line couplers, directional couplers and diplexers.


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