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12 pages, 3079 KiB

Open AccessArticle

Design of a Compact Ultra-Wideband Bandpass Filter Using Inductively Compensated Parallel-Coupled Lines

by Meechai Jamsai, Niwat Angkawisittpan and Adisorn Nuan-On

Electronics 2021, 10(21), 2575; https://doi.org/10.3390/electronics10212575 - 21 Oct 2021

Cited by 12 | Viewed by 2338

An ultra-wideband bandpass filter (UWB-BPF) using inductively compensated parallel-coupled lines (ICPCL) is presented in this article. It consists of three circuits: a high-pass filter (HPF), a lowpass filter (LPF), and a transmission line. The HPF and the LPF are independently synthesized from the [...] Read more.

An ultra-wideband bandpass filter (UWB-BPF) using inductively compensated parallel-coupled lines (ICPCL) is presented in this article. It consists of three circuits: a high-pass filter (HPF), a lowpass filter (LPF), and a transmission line. The HPF and the LPF are independently synthesized from the ICPCL. The proposed filter can suppress unwanted frequencies in the upper stopband and increase the skirt slope of the frequency response in the transition bands. The fabricated UWB-BPF with compact size provides good passband performances, with insertion loss of better than −0.49 dB and return loss of better than −12 dB in the frequency range of 2.92–10.95 GHz (the bandwidth of 8.03 GHz). The 107% bandwidth is achieved. In addition, the proposed filter can suppress the spurious frequencies at 2f₀, which is greater than 30 dB. The measured results accord well with the simulation results. The novelty of the paper is the introduction of the ICPCL for the construction of the compact UWB-BPF. Full article

(This article belongs to the Special Issue Advancements in RF, Microwave, and Millimeter-Wave Circuits and Devices)

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13 pages, 4070 KiB

Open AccessArticle

Compact Size of an Interdigital Band-Pass Filter with Flexible Bandwidth and Low Insertion-Loss Using a Folded Spiral and Stepped Impedance Resonant Structure

by Kicheol Yoon and Kwanggi Kim

Electronics 2021, 10(16), 2003; https://doi.org/10.3390/electronics10162003 - 19 Aug 2021

Cited by 5 | Viewed by 3217

Abstract

A conventional interdigital bandpass filter (BPF) is characterized by coupled and tapped lines and affords low insertion loss (IL) and easy fractional bandwidth (FBW) adjustment. However, the maximum FBW of the filter is limited to 30%, beyond that, its gap size increases, thereby [...] Read more.

A conventional interdigital bandpass filter (BPF) is characterized by coupled and tapped lines and affords low insertion loss (IL) and easy fractional bandwidth (FBW) adjustment. However, the maximum FBW of the filter is limited to 30%, beyond that, its gap size increases, thereby rendering filter fabrication impractical on a standard printed circuit board. In addition, the filter size cannot be changed because it dictates the operational frequency of the filter. Hence, in this study, we propose a compact interdigital BPF based on a spiral and folded stepped impedance resonator (SIR), which affords low IL and excellent group delay. The spiral, folded structure facilitates drastic FBW adjustment: the center frequency and adjustable range of the FBW of the designed BPF are 800 MHz and 80 to 180%, respectively. Additionally, the proposed BPF can adjust the FBW by k-factor which can adjust from 80 to 180%. The insertion and return losses of the proposed filter are 0.043 dB and 17.1 dB, respectively, and the group delay is 0.098 ns. The total filter size is only 13.8 mm × 5.98 mm, which corresponds to a size reduction by factors of >2/8 relative to a conventional filter and 2.1 relative to the latest BPF design. The group delay difference between the BPF and other filters is 0.15 ns. In addition, the range of adjustable FBW for the filter is 1.36 times different than for other filters. Full article

(This article belongs to the Special Issue Advancements in RF, Microwave, and Millimeter-Wave Circuits and Devices)

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11 pages, 4387 KiB

Open AccessArticle

Broadband Reflective Polarization Rotator Built on Single Substrate

by Xiaofan Yang, Tao Qi, Yonghu Zeng, Xiaoming Liu, Gan Lu and Qing Cai

Electronics 2021, 10(8), 916; https://doi.org/10.3390/electronics10080916 - 12 Apr 2021

Cited by 3 | Viewed by 1712

Abstract

A broadband polarization rotator built on single substrate is presented in this work. The device is designed for operation in the K and Ka bands. A slant array is used to achieve polarization rotation by 90° in a reflective manner. Broadband has been [...] Read more.

A broadband polarization rotator built on single substrate is presented in this work. The device is designed for operation in the K and Ka bands. A slant array is used to achieve polarization rotation by 90° in a reflective manner. Broadband has been obtained, with the operation frequency range covering 15–45 GHz for 3 dB criteria, which is almost 100% fractional bandwidth. In addition, the insertion loss is less than 0.3 dB over a moderate broad incident angle from 0°–20°. Furthermore, the polarization conversion ratio can be as high as 0.95. By using a bi-static method, the fabricated prototype is measured, and the measured results demonstrate satisfactory agreement with the simulation ones. In comparison with other reflective designs in the literature, this design provides good bandwidth as well as polarization conversion ratio. Miniaturization can be investigated to increase the angular stability. Full article

(This article belongs to the Special Issue Advancements in RF, Microwave, and Millimeter-Wave Circuits and Devices)

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9 pages, 2099 KiB

Open AccessArticle

Unbalanced Two-Way Filtering Power Splitter for Wireless Communication Systems

by Augustine O. Nwajana, Gerald K. Ijemaru, Kenneth L.-M. Ang, Jasmine K. P. Seng and Kenneth S. K. Yeo

Electronics 2021, 10(5), 617; https://doi.org/10.3390/electronics10050617 - 6 Mar 2021

Cited by 3 | Viewed by 2772

Abstract

A compact unbalanced two-way filtering power splitter with an integrated Chebyshev filtering function is presented. The design is purely based on formulations, thereby eliminating the constant need for developing complex optimization algorithms and tuning, to deliver the desired amount of power at each [...] Read more.

A compact unbalanced two-way filtering power splitter with an integrated Chebyshev filtering function is presented. The design is purely based on formulations, thereby eliminating the constant need for developing complex optimization algorithms and tuning, to deliver the desired amount of power at each of the two output ports. To achieve miniaturization, a common square open-loop resonator (SOLR) is used to distribute energy between the two integrated channel filters. In addition to distributing energy, the common resonator also contributes one pole to each integrated channel filter, hence, reducing the number of individual resonating elements used in achieving the integrated filtering power splitter (FPS). To demonstrate the proposed design technique, a prototype FPS centered at 2.6 GHz with a 3 dB fractional bandwidth of 3% is designed and simulated. The circuit model and layout results show good performances of high selectivity, less than 1.7 dB insertion loss, and better than 16 dB in-band return loss. The common microstrip SOLR and the microstrip hair-pin resonators used in implementing the proposed integrated FPS ensures that an overall compact size of 0.34 λg × 0.11 λg was achieved, where λg is the guided-wavelength of the 50 Ω microstrip line at the fundamental resonant frequency of the FPS passband. Full article

(This article belongs to the Special Issue Advancements in RF, Microwave, and Millimeter-Wave Circuits and Devices)

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15 pages, 5416 KiB

Open AccessArticle

A Compact Component for Multi-Band Rejection and Frequency Coding in the Plasmonic Circuit at Microwave Frequencies

by Wenxuan Tang, Yujie Hua and Tie Jun Cui

Electronics 2021, 10(1), 4; https://doi.org/10.3390/electronics10010004 - 23 Dec 2020

Cited by 7 | Viewed by 2164

Abstract

Plasmonic circuits, which support the propagation of spoof surface plasmon polaritons (SSPPs) at microwave frequencies, have been developed in recent years as an expected candidate for future highly integrated systems, mainly because of their extraordinary field confinements and sub-wavelength resolution. On the other [...] Read more.

Plasmonic circuits, which support the propagation of spoof surface plasmon polaritons (SSPPs) at microwave frequencies, have been developed in recent years as an expected candidate for future highly integrated systems, mainly because of their extraordinary field confinements and sub-wavelength resolution. On the other hand, artificial electromagnetic (EM) resonators are widely adopted in metamaterial design for flexible resonance and band gaps. In this work, an electrically small complementary spiral, which is made up of six helix branches sculptured in the ground, is proposed to achieve independent resonances at six different frequency bands. Combined with the grounded corrugated transmission line (TL), the proposed component can provide designable multi-band rejection, and compose frequency coding circuits with a compact size (less than λ₀/4). The complementary spirals excited with the bending TL and the straight one are both investigated, and independence band rejections and designed 6-bit coding sequences in the frequency spectrum are demonstrated numerically and experimentally. Hence, it is concluded that such compact components can be adopted to flexibly control the rejection of waves in multi-frequency bands, and benefits the development of frequency-identification circuits and systems. Full article

(This article belongs to the Special Issue Advancements in RF, Microwave, and Millimeter-Wave Circuits and Devices)

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11 pages, 5044 KiB

Open AccessArticle

Switchable DBR Filters Using Semiconductor Distributed Doped Areas (ScDDAs)

by Rozenn Allanic, Denis Le Berre, Cédric Quendo, David Chouteau, Virginie Grimal, Damien Valente and Jérôme Billoué

Electronics 2020, 9(12), 2021; https://doi.org/10.3390/electronics9122021 - 30 Nov 2020

Cited by 5 | Viewed by 1592

Abstract

This paper presents a novel way to switch dual-behavior resonator (DBR) filters without any additional active surface-mount components. By using a semiconductor substrate, we were able to simultaneously co-design the filters and semiconductor distributed doped areas (ScDDAs) with integrated N⁺PP⁺ [...] Read more.

This paper presents a novel way to switch dual-behavior resonator (DBR) filters without any additional active surface-mount components. By using a semiconductor substrate, we were able to simultaneously co-design the filters and semiconductor distributed doped areas (ScDDAs) with integrated N⁺PP⁺ junctions as active elements. These ScDDAs act as electrical vias in the substrate, which makes it possible to have an open-circuited resonator in the OFF state and a short-circuited resonator in the ON state, and, consequently, to control the transmission zeroes of the filters. This method offers degrees of freedom as the dimensions and positions of these doped areas can be chosen to obtain the best performances. In this study, four filters were simulated and fabricated to spotlight different possibilities for the dimensions and positions of the ScDDA to control the low- or high-frequency transmission zero of the filters. The simulations were in very good agreement with the measured results. All the filters present insertion losses lower than 2 dB in the OFF and ON states, a great flexibility in the frequency choice, and good agility compared with the state of the art. Full article

(This article belongs to the Special Issue Advancements in RF, Microwave, and Millimeter-Wave Circuits and Devices)

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9 pages, 6216 KiB

Open AccessArticle

Dynamic Modulation Band Rejection Filter Based on Spoof Surface Plasmon Polaritons

by Weigao Yang, Lixiang Liu, Xiaoqiang Su, Lijuan Dong, Yanhong Liu and Zhanfeng Li

Electronics 2020, 9(6), 993; https://doi.org/10.3390/electronics9060993 - 13 Jun 2020

Cited by 8 | Viewed by 2181

Abstract

In this paper, we proposed a dynamic modulation band rejection filter based on the spoof surface plasmon polaritons (SSPPs) waveguide. The dynamic adjusting mainly derives from changing the capacitance between the U-shape and the waveguide configuration. The capacitance can modulate the cut-off frequency [...] Read more.

In this paper, we proposed a dynamic modulation band rejection filter based on the spoof surface plasmon polaritons (SSPPs) waveguide. The dynamic adjusting mainly derives from changing the capacitance between the U-shape and the waveguide configuration. The capacitance can modulate the cut-off frequency of fundamental mode. The rejection band is formed by the high order propagation mode and the cut-off frequency of fundamental mode. We analyzed the dispersion curve and transmission performance of the band rejection filter with different capacitances. Compared with the previous scheme, the design we proposed here has a simpler and more delicate configuration to process and decreases the mechanical error. We experimentally demonstrated the excellent performance of the device by changing the direct voltage loaded on the varactor diode and achieved real time modulation around 2 GHz. Full article

(This article belongs to the Special Issue Advancements in RF, Microwave, and Millimeter-Wave Circuits and Devices)

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16 pages, 5889 KiB

Open AccessArticle

Simplified Modal-Cancellation Approach for Substrate-Integrated-Waveguide Narrow-Band Filter Design

by Sebastian Celis, Mohamed Farhat, Abdullah S. Almansouri, Hakan Bagci and Khaled N. Salama

Electronics 2020, 9(6), 962; https://doi.org/10.3390/electronics9060962 - 9 Jun 2020

Cited by 4 | Viewed by 2941

Abstract

Current substrate-integrated-waveguide (SIW) filter design methodologies can be extremely computational and time-inefficient when a narrow-band filter is required. A new approach to designing compact, highly selective narrow-band filters based on smartly positioned obstacles is thus presented here. The proposed modal-cancellation approach is achieved [...] Read more.

Current substrate-integrated-waveguide (SIW) filter design methodologies can be extremely computational and time-inefficient when a narrow-band filter is required. A new approach to designing compact, highly selective narrow-band filters based on smartly positioned obstacles is thus presented here. The proposed modal-cancellation approach is achieved by translating or eliminating undesired modes within the frequency of interest. This is performed by introducing smartly located obstacles in the maxima and nulls of the modes of interest. This approach is different from the traditional inverter technique, where a periodic number of inductive irises are coupled in a ladder configuration to implement the desired response of an nth-order filter, and significantly reduces the complexity of the resulting filter structure. Indeed, the proposed method may be used to design different filters for several frequency bands and various applications. The methodology was experimentally verified through fabricated prototypes. Full article

(This article belongs to the Special Issue Advancements in RF, Microwave, and Millimeter-Wave Circuits and Devices)

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