Dual-band Frequency Response Research Articles

Design of Miniature UWB-Based Antenna by Employing a Tri-Sectional SIR Feeder

A novel ultra-wideband (UWB)-based microstrip antenna is presented in this work by using a slotted patch resonator, a tri-sectional stepped impedance resonator (SIR) feeder, as well as a reduced ground plane. The whole structure was realized on an FR4 substrate. The impact of incorporating several cases of ground planes on the input reflection has been thoroughly investigated under the same tri-sectional SIR feeder and by employing a slotted patch radiator. Since the complete ground plane presents an inadequate frequency response, by reducing the ground plane, the induced UWB responses are apparent while the antenna exhibits higher impedance bandwidth. The impact of both the uniform impedance resonator (UIR) as well as the SIR feeder on the input reflection has also been examined by following the same adopted reduced ground technique and using a slotted patch radiator. As a result, the UIR feeder exhibits a dual-band frequency response, when a wide notched band is incorporated in the range from 4.5–6.5 GHz. The dual-band response of the bi-sectional SIR feeder is still apparent with a narrower notched band in the frequency range from 4–5 GHz. As far as the tri-sectional SIR feeder is concerned, the UWB response is discernible without recording the existence of a notched band. Additionally, the antenna displays a higher impedance bandwidth compared with the previously reported steps. Our proposed antenna configuration is designed with highly compact dimensions and an overall size of 14 × 27.2 mm2. Moreover, it operates under the impedance bandwidth of 2.86–10.31 GHz that can be leveraged for numerous applications where wireless systems are used. Our approach presents several advantages compared with the other reported UWB-based antennas in the literature, whereas the measured S11 pattern is in good agreement with the simulated one.

Design of dual‐band filtering power dividers with designable port‐to‐port isolation network

In this article, a class of dual-band filtering power dividers is proposed with simultaneous realization of good designable port-to-port isolation. A filtering branch, including two cascaded stub-loaded half- wavelength resonators and coupled-line sections, are introduced together with the proposed isolation network to simultaneously achieve controllable bandwidth, frequency ratio in dual-band power division, as well as the port-to-port isolation. To construct dual-wideband power division, two coupled multimode resonators could be used to form the filtering branches, while the proposed isolation network with additional open stub at each output port is utilized to obtain a wide port-to-port isolation band. Theoretically, a design method for analyzing the dual-band frequency response of the power division is presented, while a dual- or wide-band isolation is achieved by introducing multiple transmission zeros in the S32-magnitude. Finally, two prototype power dividers on the microstrip-line structure are designed and fabricated. The simulated and measured results agree well with each other, which verify the theoretical predications.

Concurrent Dual-Band Inverter-Based Low Noise Amplifier (LNA) for WLAN Applications

low noise amplifier (LNA); concurrent; dual-band; inverter-basedIn this paper, a two-stage concurrent dual-band low noise amplifier (DB-LNA) operating at 2.4/5.2-GHz is presented for Wireless Local Area Network (WLAN) applications. The current-reused structure using resistive shunt-shunt feedback is employed to reduce power dissipation and achieve a wide frequency band from DC to-5.5-GHz in the inverter-based LNA. The second inverter-based stage is employed to increase the gain and obtain a flat gain over the frequency band. An LC network is also inserted at the proposed circuit output to shape the dual-band frequency response. The proposed concurrent DB-LNA is designed by RF-TSMC 0.18-µm CMOS technology, which consumes 10.8 mW from a power supply of 1.5 V. The simulation results show that the proposed DB-LNA achieves a direct power gain (S 21 ) of 13.7/14.1 dB, a noise figure (NF) of 4.2/4.6 dB, and an input return loss (S 11 ) of −12.9/−14.6 dBm at the 2.4/5.2-GHz bands.

Design of wide band compact bend triangular resonator artificial magnetic conductor and its application for antenna gain enhancement

SummaryIn this paper, a compact bend triangular resonator (CBTR) structure is proposed as artificial magnetic conductor (AMC) to enhance antenna gain for wide frequency bandwidth. This paper presents the metamaterial properties of the CBTR structure like absorbance and reflection phase. The CBTR unit cell gives in‐phase reflection (0° ± 90°) for 55.2% bandwidth. The CBTR unit‐cell reflection phase analysis is presented for the different height of normal incident wave. The CBTR AMC performance is validated using a wideband dipole antenna. For −6‐dB impedance bandwidth, the standalone dipole antenna covers ultrawide frequency range 3.1–12 GHz and for −10‐dB impedance bandwidth, antenna has dual band frequency response 3.4–4.4 GHz and 8.3–11 GHz. The antenna shows good impedance matching and radiation characteristics for frequency range, where the unit‐cell reflection phase is 135° to 45° for frequency range 2.5–6.5 GHz (bandwidth of 88.8%). The broadside directivity of 7 dBi is achieved for the dipole antenna with CBTR AMC in the frequency range of 2.5–6.5 GHz and broadside gain of >5 dBi in the frequency range of 3.2–6.7 GHz (bandwidth of 70.7%). The antenna efficiency of 60% (minimum) is achieved for the frequency range of 3.68.0 GHz (75.8%). The proposed CBTR design is orthogonally symmetric and is useful for dual‐polarized wideband frequency applications like wireless local area network (WLAN) (2.4–2.5 and 5.15–5.85 GHz) and new radio (NR) 5G sub‐6‐GHz (3.3–5.0 GHz).

Single-Layer Mode Composite Coplanar Waveguide Dual-Band Filter With Large Frequency Ratio

A dual-band filter of a large frequency ratio is proposed, studied, and developed in this article, which is based on mode composite coplanar waveguide (MCCPW). Both low and high bands of the dual-band filter can be designed independently with a high degree of design freedom. The filter can achieve more than ten times the frequency difference between the two bands, which is usually hard to accomplish by conventional dual-band filter design techniques. All harmonics between the two bands can be suppressed by a cascaded low-pass filter and impedance matching structure to form a qualified dual-band frequency response. The characteristic of the proposed MCCPW dual-band filter makes it a promising candidate for multiband systems, especially in 5G communication systems. The demonstrated MCCPW dual-band filter is fabricated with a single-layer substrate. Measured results are in good agreement with simulated results, which validate the feasibility and superiority of the proposed filtering technique.

Design of Dual-Polarized Frequency Selective Rasorber With Two Independent Transmission Windows Using Multi-Resonators

In this paper, a dual-polarized frequency selective rasorber (FSR) with two independent transmission windows and three absorption bands is designed and characterized. The proposed FSR is composed of the resistive sheet and the bandpass frequency selective surface (FSS), which are separated by the air spacer. At the top resistive sheet, two concentric modified square loops with different lengths are inserted into the square loop with four lumped-resistor-loaded legs, which provides two independent transmission windows. The bottom bandpass FSS, consisting of the combination of the square slot and the four-leg arrow shaped slot, is adopted to realize the same transmission bands as the upper resistive sheet. Performance of the proposed FSR is investigated via its equivalent circuit model and full-wave simulations. The simulated results exhibit dual-band frequency response, which has two independent transmission windows within three absorption bands. The two pass-bands operate at 8.5GHz and 13GHz with insertion loss of 0.31dB and 0.48dB, respectively. And the three absorption bands are in the range of 4.1GHz-7.5GHz, 9.1GHz-12.3GHz, and 14GHz-19.7GHz, respectively. Also, the band with reflection coefficient lower than −10dB covers from 4.2 GHz to 19.6GHz and the fractional bandwidth is up to 129.4%. Furthermore, prototype of the FSR is fabricated and measured. Good agreements between the measured and the simulated results can be observed.

Performance Analysis of a Defected Ground-Structured Antenna Loaded with Stub-Slot for 5G Communication.

In this paper, a defected ground-structured antenna with a stub-slot configuration is proposed for future 5G wireless applications. A simple stub-slot configuration is used in the patch antenna to get the dual band frequency response in the 5G mid-band and the upper unlicensed frequency region. Further, a 2-D double period Electronic band gap (EBG) structure has been implemented as a defect in the metallic ground plane to get a wider impedance bandwidth. The size of the slots and their positions are optimized to get a considerably high impedance bandwidth of 12.49% and 4.49% at a passband frequency of 3.532 GHz and 6.835 GHz, respectively. The simulated and measured realized gain and reflection coefficients are in good agreement for both operating bandwidths. The overall antenna structure size is 33.5 mm × 33.5 mm. The antenna is fabricated and compared with experimental results. The proposed antenna shows a stable radiation pattern and high realized gain with wide impedance bandwidth using the EBG structure, which are necessary for the requirements of IoT applications offered by 5G technology.

Multi-Semicircle-Based Single- and Dual-Band Frequency-Selective Surfaces: Achieving Narrower Bandwidth and Improved Oblique Incidence Angular Stability

This article proposes two new frequency-selective surface (FSS) designs based on specific combinations of a multiple number of semicircles. One of the proposed designs makes use of four semicircles, yielding a single-band frequency response. The other consists of a combination of eight semicircles arranged in a square-like shape, producing a dual-band frequency response. The proposed designs were simulated with commercial electromagnetic simulation software.

Mathematical Analysis of Microstrip Diplexer Design for WLAN System

Miniature microstrip diplexer at band frequencies of (1.45/1.95GHz and 2.5/3.5GHz) in two considered channels using the coupled stepped impedance resonators (SIRs) has been presented in this study with mathematical analysis. This diplexer has dual pairs of coupled SIRs with impedance ratio and the source-load coupling lines. As a result of the tuning of impedance ratio and length ratio of SIRs, the resonant modes are possibly determined to achieve 2nd order bandpass filter (BPF) with dualband frequency responses for the investigated diplexer. The investigated microstrip diplexer has a simple outline, compact dimensions, an in effect design technique and straightforward calculations of impedance, electrical lengths, fractional bandwidth, coupling factors and other electrical specifications.

Dual Band Planar Inverted F Antenna (PIFA) with L-Shape Configuration

One of the most used antennas in mobile devices is planar inverted F antenna (PIFA). PIFA can be design in dual band frequencies due to the coverage of the wireless service in a mobile device that requires a multiple frequencies. However, the consideration of technical operation has to be combined with an evaluation of the antenna radiation impact on the users. A procedure of PIFA work in GSM (867-960MHz) and GSM (1710-1899MHz) is done using CST Software. The dual band frequency response is obtained by means of an insertion of an L-shaped slot, which is use to tune the operation frequencies. The prototype of the antenna is fabricated as model by CST Software and evaluated. It is found out that the PIFA antenna has a good efficiency, bandwidth as well as produce a maximum gain for the antenna. A key and innovative research is still underway to broaden performance parameters of the antenna.

Dual-Band High-Temperature Superconducting Bandpass Filter Using Dual-Mode Hairpin Ring Resonator

A compact dual-band high-temperature superconducting (HTS) bandpass filter using a novel hairpin ring resonator (HRR) is presented in this paper. The proposed HRR that provides two controllable resonant modes can be applied to construct dual-band frequency response conveniently. The resonance mechanism of modes and coupling property between resonators are well investigated. Then, four identical HRRs are cascaded for achieving a high-performance dual-band filter. Finally, a fourth-order HTS filter centered at 1.9 and 2.6 GHz is successfully designed and fabricated on MgO substrate with YBCO thin films. The obtained filter has a compact size (occupies only 17.6 mm × 14 mm). The measured results show a high performance and agree well with the simulated ones.

Dual-band Band-pass Filters Based on Metallic Via Holes

Abstract This paper presents compact dual-band band-pass filters (BPFs) using microstrip transmission lines (TLs) loaded with metallic via holes (MVHs). The primary goals of the proposed design are to get size reduction and dual-band frequency response. An end-coupled line dual-band BPF with better size reduction has been obtained using MVHs as a single negative (SNG) metamaterial (MTM) component to achieve negative relative permittivity (ɛ r ). This component is adequate for designing dual-band BPFs to operate at 4.1 GHz and 6 GHz resonant frequencies. To the best knowledge of the authors of this work, “Dual-” band BPF based on MVH has not been experienced yet by any other work in the literature. The filters structure length is as small as one third of wavelength. The filters have been designed with a fractional bandwidth (δ) that exceeds 10% at the resonant frequencies. Numerical observations of the microstrip TL and end-coupled BPFs designs have all been discussed. Simulations were done by HFSS software and implemented on the substrate Roger RO3210 with dielectric constant of 10.8 and dielectric substrate height of 1.27 mm. These filters are convenient for most common microwave applications.

Analysis and design of frequency selective surfaces using teragon patch elements for WLAN applications

This paper describes a fractal design methodology for frequency selective surfaces (FSSs) composed of teragon metallic patches on a single-layer fiberglass dielectric. Shapes presented by teragons are exploited to design compact FSSs acting as dual-band band-stop spatial filters. An FSS parametric analysis is performed in terms of the fractal dimension and unit cell size of fractal patches. The transmission properties of the proposed periodic arrays are initially investigated through simulations performed by Ansoft DesignerTM commercial software. To validate the used methodology, three FSS prototypes are selected for fabrication, and one of them is designed to reject wireless local area network signals in the bands of 2.4–2.5 GHz (IEEE 802.11b) and 5.0–6.0 GHz (IEEE 802.11a). Experimental characterization of the FSS prototypes is accomplished through an alternative setup with elliptical monopole microstrip antennas for low-cost FSS measurements. The obtained results point to interesting features for FSS spatial filters: compactness, with high values of frequency compression factor (up to 80.4%); dual polarization; dual-band frequency responses; and stable resonance frequencies at oblique incidence.

Design and Experimental Performance of Diplexing MMIC Distributed Amplifier

An MMIC distributed amplifier with dual band frequency response and diplexing functionality is designed and measured. Using a band-pass artificial transmission line, two frequency bands, Spanish satellite broadcast TV band (11.7-12.5 GHz) and the mobile TV link (10.0-10.7 GHz), can be amplified and extracted at different physical ports. Experimental results exhibit quite good agreement with simulations and demonstrate the viability of these amplifiers in MMIC technology.

Compact Split-Type Dual-Band Bandpass Filter Based on $\lambda/4$ Resonators

This letter presents a compact split-type dual-band bandpass filter based on the λ/4 resonators, whereas the filter's dual-band frequency response is achieved by creating a stopband inside a virtual wide passband. Besides the uniform microstrip λ/4 resonators, dimensions of both required <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i> and <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> inter-resonator inverters for the proposed coupling topology are analytically derived based on the synthesized coupling matrix. In parallel, the hook-type coupled line is designed not only to provide the desired external and cross I/O ports' couplings, but also to manipulate the associated finite transmission zero as demanded in getting an improved upper stopband. To justify our proposed idea, a split-type dual-band BPF with central frequencies at 1.8 and 2.45 GHz, and fractional bandwidths of both 5.0% are designed. These closely proximate dual passbands are primarily realized by properly allocating two finite transmission zeros between them at 2.13 and 2.29 GHz. Moreover, an extra pair of transmission zeros at 1.53 and 3.04 GHz, contributed by cross I/O ports' coupling, is produced at lower and higher sides of virtual wide passband, thus enhancing the out-of-band rejection ratios. The final measured and simulated results show good consistence with the theoretical counterparts.

메타물질 전송선로를 이용한 이중대역 평형증폭기

This paper describes a design of dual band balanced amplifier using a lefted handed meta-material transmission line structure for high frequency application. Meta-material transmission lines have been known to have dual band frequency responses. A dual band branch line hybrid coupler is designed using the meta-material transmission lines, and measured at first. Two identical dual band amplifiers are also designed, built and tested using the same meta-material transmission structure. The proposed dual band balanced amplifier is composed of those dual band branch line hybrid coupler and amplifiers. In order to suggest an design example, a prototype of dual band balanced amplifier is built and measured at the dual frequencies, 1800㎒(f₁) and 2300㎒(f₂). The simulation and measurement show that the fabricated balanced amplifier operates well at the desired dual frequencies bands with the gain of 11.12㏈ and 17.67㏈ at f₁ and f₂, respectively, with a good agreement with the simulation results.

Dual-Band Multi-Pole Directional Filter for Microwave Multiplexing Applications

A novel microstrip directional filter for multiplexing applications is presented. This device uses composite right-left-handed transmission lines and resonators to achieve dual-band frequency response. In addition, by cascading two or more stages using dual frequency immitance inverters, multi-pole configurations can be obtained. Simulation and experimental results are presented with good agreement.

A Design of Dual Band Amplifier Using Left Handed Transmission Lines

This paper describes a design of dual band amplifier using left handed (LHJ) transmission line, which is a part of composite right/left handed (CRLH) transmission line. It is well known that CRLH transmission lines show dual band frequency response. At first, two single-band amplifiers for frequency f1 and f2 are designed, and their matching networks at both amplifiers are synthesized into the dual band matching network by adopting CRLH structure. As an example for proving the validity of the proposed design, a dual band amplifier operating at 1800MHz and 2300MHz is designed, fabricated and measured. The simulation and measurement show that the proposed amplifier operates well at the desired dual bands with the gain of 13.65dB and 19dB at 1850MHz and 2360MHz, respectively, and a good matching performances. In addition, a quite good agreement between the simulation and measurement is observed.

Dual-Band Mixer Using Composite Right/Left-Handed Transmission Lines

The concept of composite right left-handed transmission lines provides for one additional degree of freedom in realizing arbitrary dual-band frequency response devices. In this letter, an arbitrary dual-band operation mixer, based on the classical balanced mixer topology is proposed. The prototype demonstrates the mixer performance for a ratio of 2.5 between the two operation bands (860 MHz and 2,150 MHz). The conversion losses are better than 8.5 dB in both bands.