Dual-band Operation Research Articles

Modeling and Design of a Rear-Mounted Underwater Projector Using Equivalent Circuits.

Tonpilz is a popular transducer for underwater projector arrays for sonar systems. For low-frequency transmission, a larger axial dimension of the conventional Tonpilz transducer is required. However, a bulky and heavy Tonpilz element is not suitable due to limitations in terms of the space and payload of the array platform. To address this problem, we developed a rear-mounted Tonpilz transducer to generate a sub-fundamental resonance in addition to the common longitudinal resonance. For this purpose, we developed a new equivalent circuit model that can reflect all the effects of the key design parameters of the transducer, such as suspension thickness (stiffness), tail mass thickness, and head mass thickness. The impedance and transmitting voltage response were evaluated as performance factors at both resonance frequencies. The validity of the circuit was verified by comparing the analysis results with those from the finite element analysis of the same transducer. Based on the results, the transducer structure was designed to have comparable transmitting performance at both resonance frequencies by employing relatively high suspension stiffness, light tail mass, and heavy head mass. The novel design can permit the dual-band operation of the transducer so that the transducer can operate as a wideband projector.

Dual-Band 2 × 2 MIMO Antenna with Compact Size and High Isolation Based on Half-Mode SIW

This paper presents a close-spaced dual-band 2 × 2 multiple-input multiple-output (MIMO) antenna with high isolation based on half-mode substrate integrated waveguide (HMSIW). The dual-band operation of the antenna element is achieved by loading a rectangular patch outside the radiating aperture of an HMSIW cavity. The HMSIW cavity is excited by a coaxial probe, whereas the rectangular patch is energized through proximity coupling by the radiating aperture of HMSIW. The antenna elements can be closely placed using the rotation and orthogonal arrangement for a 2 × 2 array. Small neutralization lines at the center of the MIMO antenna can increase the isolation among its elements by around 10 dB in the lower band and 5 dB in the higher band. A prototype of the MIMO antenna is fabricated and its performance is measured. The measured results show that the resonant frequencies are centered at 4.43 and 5.39 GHz with bandwidths of 110 and 80 MHz and peak gains of 6 and 6.4 dBi, respectively. The minimum isolation in both bands is greater than 35 dB. The envelope correlation coefficient is lower than 0.005 within two operating bands.

Quadrature Sandwich Rectenna for Wireless Power Transfer

This novel work presents a quadrature sandwich rectenna circuit for collecting RF from four inputports at different angles. The scheme's high efficiency and increase in output power are significant for theoperation of wireless electronic devices. This work demonstrates the requirements of self-powering.Specifically, simulation efficiency is shown to achieve 77%, and input power is 0 dBm for a 5 KΩ resistanceload and dual-band operation. The results of this experiment are encouraging in terms of wireless powering ofsome devices in wireless telecommunication systems. This scheme can also be applied to radio frequencywireless power transfer and harvesting, and would be useful in industrial, scientific, and medical applications.Furthermore, its mode of operation is sustainable, and it is compact.

Dual-Band Microstrip Resonant Sensor for Dielectric Measurement of Liquid Materials

A novel compact microstrip resonant dielectric permittivity sensor with dual-band operation is presented in this paper. The circuit makes use of a single stepped-impedance-resonator as the sensing element, working at the 2.45-GHz and 5.8-GHz ISM bands, under differential and common modes, respectively. Sensitivity of the circuit and resonator coupling at each band can be configured independently. Moreover, testing of the sample is done by using a single sensing region without the need of duplicating the sample location. Experimental measurements are carried out using a very small amount of liquids and the results are presented validating the theory. This work delivers a compact, reusable, label-free and non-destructive microwave device and paves a way for sensing dielectric properties of chemicals with accuracy due to the dual-band performance.

Analysis of the Propagation Constant of a Ridge Gap Waveguide and Its Application of Dual-Band Unequal Couplers

In this article, an analysis of the propagation constant and the characteristic impedance of a ridge gap waveguide (RGW) is proposed, which includes the comparison of the phase variation between three kinds of guiding structures, the approximation for the propagation constant of RGW, and the variation of characteristic impedances and phase characteristics. According to the analysis, the RGW technology, rather than the traditional microstrip transmission line, is utilized to implement two dual-band unequal couplers operating at two frequency bands. Furthermore, a coupler is fabricated and measured, exhibiting a dual-band operation with a power-dividing ratio of 2 dB and a quadrature phase difference with the same sign between two output ports.

High-energy square-wave pulses generated in a 1/1.5-µm dual-band mode-locked fiber laser.

The generation of square-wave pulses in a 1/1.5-µm dual-band mode-locked fiber laser is experimentally demonstrated. The laser is based upon a peculiar "figure-θ" architecture that exploits a single active fiber to realize dual-band operation. High-energy square-wave pulses are simultaneously generated in both the 1-µm and the 1.5-µm spectral band using the laser. The 1-µm pulse maintains wave-breaking-free operation during the increase of the pump power and finally achieves energy as high as 88.6 nJ, while the 1.5-µm pulse achieves energy up to 1.5 µJ before it ultimately collapses into second-order mode locking. To the best of our knowledge, this is the first report on the formation of square-wave pulses in dual-band mode-locked fiber lasers.

A tunable metamaterial-based linear-to-circular polarization converter regulated solid state plasma in S-band

As the most widely used band in wireless communication systems, S-band is often used in many military and civil fields. In this paper, with the aid of the reconfigurability realized by the solid state plasma (SSP), a tunable metamaterial-based polarization converter is proposed and theoretically investigated. Through the premeditated excitation of the SSP resonators in the specific region, the linear-to-circular polarization conversions with two different operating states can be realized and switched to each other. The numerical results show that the polarization converter can obtain circularly polarized waves in two separate bands (2.15–2.63 GHz and 3.18–3.71 GHz) when our design is in State I, and the dual operating bands expands and merges into a consecutive ultra-wideband range (2.04–3.67 GHz) when our design is switched to State II. The total tunable working range of the presented polarization converter can essentially cover the whole S-band and the phenomenon of the isolation and fusion of the operating band possesses great potential application value in the fields of radar radomes, polarization separation, electromagnetic shielding, and so on.

Wearable Dual-Band and Dual-Polarized Textile Antenna for On- and Off-Body Communications

A wearable all-textile microstrip patch antenna (MPA) operating in the dual bands of medical body area network (2.36–2.40 GHz) and WiMAX (3.4–3.6 GHz), is proposed for body-centric communications. The omnidirectional radiation pattern with linear polarization for on-body link and unidirectional radiation pattern with circular polarization for off-body link are achieved by introducing reactance loading into MPA. Notably, two pairs of shorting pins are employed to tune the TM10 mode of MPA and generate a new mode of TM00, and by adjusting the spacing and radii of shorting pins, the required dual-band and dual-mode operation is achieved. Moreover, due to the adoption of textile (i.e., wool felt) as substrate and nylon conductive fabric as conductor, the antenna is flexible, totally conforming to the human body. The proposed MPA, with the dimensions of 70 mm × 70 mm × 2 mm (0.56λ0 × 0.56λ0 × 0.016λ0 at 2.38 GHz), was fabricated and characterized. The measured results show that the reflection coefficient, radiation pattern, and gain of the antenna are slightly affected by structural deformation and human body loading. With merit characteristics, the proposed design can be well applied to wearable medical applications.

Dual-band B-shaped antenna array for satellite applications

AbstractThe paper presents a 1 × 2 B-shaped antenna array for dual-band operation at 4 and 8 GHz. The antenna design consists of a rectangular patch with two annular-strip lines fabricated on the top layer and finite ground plane on the bottom layer. The array is formed by designing an optimum T-shaped microstrip line for impedance matching. The dimensions of the antenna array are 78 × 36 × 1.6 mm3. Full-wave simulations have been conducted and the measured results are in good consent with the simulated results. The measured impedance bandwidth (reference −10 dB) has been observed at 3.84–4.16 and 7.78–8.38 GHz. Measured peak gain and radiation efficiency at 4 and 8 GHz are 8.3, 9.4 dB and 82.5 and 81.2%, respectively.

Implantable Antennas for Bio-Medical Applications

Biomedical telemetry has gained a lot of attention with the development in the healthcare industry. This technology has made it feasible to monitor the physiological signs of patient remotely without traditional hospital appointments and follow up routine check-ups. Implantable Medical Devices (IMDs) play an important role to monitor the patients through wireless telemetry. IMDs consist of nodes and implantable sensors in which antenna is a major component. The implantable sensors suffer a lot of limitations. Various factors need to be considered for the implantable sensors such as miniaturization, patient safety, bio-compatibility, low power consumption, lower frequency band of operation and dual-band operation to have a robust and continuous operation. The selection of the antenna is a challenging task in implantable sensor design as it dictates performance of the whole implant. In this paper a critical review on implantable antennas for biomedical applications is presented.

Compact wearable dual wideband circularly polarized L-strip fed slotted textile antenna with parasitic elements for ISM band applications

This paper presents an L-strip fed compact wearable dual wide band circularly polarized textile antenna (DWCPTA) with a pair of parasitic elements and dual wide band operations at frequencies 2.45 and 5.80 GHz for industrial, scientific and medical (ISM) band applications. The antenna is printed on top of denim (jeans) substrate having dielectric constant 1.7 and thickness of 1.43 mm with wide slot ground plane on back side. The proposed DWCPTA of size 40 × 40 × 1.43 mm3 achieves -10 dB simulation impedance bandwidth of 89.16% (2.3 – 6.0 GHz) and 3-dB axial ratio bandwidth (ARBW) of 47.55% (2.34 – 3.80 GHz) and 12.60% (5.20 – 5.90 GHz) and essentially, low specific absorption rate (SAR) values of 0.8 and 0.95 W/Kg over 10 g of human tissues for wide band operations at frequencies 2.45 and 5.80 GHz respectively. The proposed DWCPTA is designed, fabricated and tested, which shows good agreement between measured and simulated ones.

A Flipping UHF RFID Sensor-Tag for Metallic Environment Compliant With ETSI/FCC Bands

A novel dual-band ultrahigh-frequency (UHF) radio frequency identification (RFID) sensor tag, designed to operate on metallic surfaces, is proposed. This particular UHF RFID sensor tag is capable of operating in both the main RFID frequency bands of the European Telecommunications Standards Institute (ETSI) and the Federal Communication Commission (FCC). The dual-band operation of the UHF RFID sensor tag is based on a very simple concept; by flipping the UHF RFID sensor tag on a metallic surface, it can operate either in the ETSI or FCC RFID frequency bands. The impedance and radiation characteristics of the UHF RFID sensor tag are presented with an extensive analysis of the effects of the metallic surface on the UHF RFID sensor tag. In addition, an equivalent model of the UHF RFID sensor tag, which includes the effects of the metallic surface on the sensor tag, is proposed. The UHF RFID sensor tag has a small form factor and presents a satisfying read range of around 3 m for both the operating frequency bands in a metallic environment as well as a read range of 1.4 m when operating in free space.

Dual-Band Reflective Metagratings With Interleaved Meta-Wires

We propose a new topology for printed circuit board metagratings (MGs) for manipulation of electromagnetic waves at microwave frequencies. By interleaving two single-band segmented gratings (SGs), a composite device capable of performing dual-band operation is realized. The constituent SGs are designed independently, meaning the two operating frequencies need not be harmonically related. The SGs are shielded from one another through inclusion of via fences which suppress near-field coupling. They are each engineered to be inactive within the other's operating band, which helps retain their individually encoded functionalities. Using the proposed topology, a dual-band MG that performs perfect anomalous reflection of plane waves at 10 and 15.11 GHz is designed. The device is verified both numerically and experimentally.

A Novel Miniature Dual-Band Impedance Matching Network for Frequency-Dependent Complex Impedances

In this article, a novel dual-band impedance matching network capable of providing impedance matching between frequency-dependent complex impedances at two frequencies is reported. The proposed dual-band impedance matching network employs the dual-band design of bridged-T coil, such that a very compact circuit size and dual-band operation can be achieved at the same time. Various design examples are presented to demonstrate the versatile property of the proposed dual-band impedance matching network, along with a rigorous analysis of its practical limitations. Also, two design examples of the proposed dual-band impedance matching network are implemented using the integrated passive device technology for performance validation.

Design of Metal Insulator Metal based Square Ring Resonator Plasmonic Filter using Silica Slits for Dual Band Applications

In this paper, Metal-Insulator-Metal (MIM) based dual-band plasmonic bandpass filters (BPF) with single and dual silica slits design and analysis is presented. The Square Ring Resonator (SRR) is coupled using Coupled feed line for dual-band operations. The coupled feed line is used for dual-band operating wavelengths, 1300 nm (230.6 THz) and 1600 nm (187.37 THz). Design and simulations are performed using complex electromagnetic simulatorknown as computer simulation technology (CST) microwave tool. The proposed filters are used for plasmonic single and dual-band bandpass filter (BPF) applications in photonic integrated circuits (PIC’s).

Performance analysis of 65 nm CMOS LNA using SSL technique for 5G cellular front-end receivers

This paper presents a performance analysis of a wideband low noise amplifier (LNA) that utilizes a 65 nm CMOS Samsung mm-wave process. The proposed CMOS LNA designed with new built-in techniques will overcome the challenges faced by device parasitic and electromagnetic (EM) losses. A suspended substrate line (SSL) is characterized and analyzed with its dual-band operation and achieves excellent EM compatibility. The traditional EM losses in bulk active and passive components have been incurred using built-in techniques to provide better linearity of LNA. The proposed mm-wave LNA enables it’s each family component to avoid leakage of EM waves and its interconnected parasitic losses in layout. An SSL based parallel-series network is optimized to achieve a wide bandwidth of 26 GHz to 34 GHz. The full design of LNA achieves the highest peak gain of 25 dB by using proper 50 Ω matching constraints over the wideband response of 27.8 GHz to 32.5 GHz. The fabricated chip of LNA is given a supply voltage of 1.2 V, and the calculated chip area is 0.35*0.22 mm2. The simulation and measurement results demonstrate the minimum noise figure of 2.5 dB and achieve the highest stability factor in the desired band of operation. The LNA also measured linearity with a 1 dB compression point where input power of −19dBm has obtained at 30.5 GHz.

A compact double-band planar printed slot antenna for sub-6 GHz 5G wireless applications

AbstractA planar rectangular slot antenna with dual-band operation and realized higher peak gain is proposed, designed, and fabricated for sub-6 GHz 5G applications. The antenna possesses a rectangular radiating slot with the inverted stub on its upper edge excited simultaneously by a micro-strip feed line having a double folded T-shaped structure. The fabricated design is of compact size with the radiating portion of 0.3 λ0 × 0.17 λ0 (λ0 represents free-space wavelength) and profile of 0.009 λ0. The measured results show the operating frequency bands of 3.29–3.63 GHz and 4.3–5.2 GHz, with a peak gain of around 7.17 dBi. The higher frequency band is generated by the feed patch and the slot whereas lower resonant frequency band is generated by the stub loaded on the slot. The measured results are in a good agreement with the simulated results. The proposed design is suitable for the International Telecommunications Union sub 6 GHz applications.

Reconfigurable 2.4-/5-GHz Dual-Band Transmitter Front-End Supporting 1024-QAM for WLAN 802.11ax Application in 40-nm CMOS

This article presents a new design methodology of a reconfigurable dual-band output matching network with high efficiency. The implemented output matching network achieves a passive efficiency of 71.6% and 75% at 2.4 and 5.5 GHz, respectively. Based on the proposed output matching network, a transmitter and a standalone power amplifier (PA) supporting 2.4-/5-GHz dual-band operation for the emerging wireless local area network (WLAN) 802.11ax application are designed and fabricated in 40-nm CMOS technology. In 2.4- and 5-GHz WLAN bands, the PA achieves a P sat of 23 and 21.9-22.4 dBm with power-added efficiency (PAE) of 27% and 24.2%-28.2%, respectively. At 2.442 GHz, the transmitter delivers 8.1-dBm average output power for 40-MHz, 1024-quadrature amplitude modulation (QAM) 802.11ax signal while meeting the standard specification of error vector magnitude (EVM) below -35 dB. In 5-GHz operating mode, the transmitter achieves an average output power of 6.72-6.95 dBm with the EVM of -35 dB for 80-MHz, 1024-QAM 802.11ax signal. The PA and transmitter front end are the first published designs for dual-band WLAN 802.11ax application in the literature.

Dual Q/V-Band SiGe BiCMOS Low Noise Amplifiers Using Q-Enhanced Metamaterial Transmission Lines

This brief presents two dual-band low noise amplifiers (LNAs) in Q/V-band fabricated in 0.18-μm SiGe BiCMOS technology. The developed LNAs function over the dual (44/60 GHz)-band with an integrated filtering function and achieve peak power gain of 19.1 dB with minimal gain imbalance of less than 0.2 dB between the two bands. The achieved 3-dB bandwidths are more than 6 GHz for each band of the two LNAs with the lowest measured noise figure of 5.6 dB in the targeted frequency bands. The synthesized Q-enhanced metamaterial transmission line structures proposed in this brief contribute a dual-band operation at 44/60 GHz with a rejection of more than 30 dB between the two bands. The Colpitts style negative generation circuit is utilized in conjunction with composite right/left-handed metamaterial transmission line and its dual structure, which is unprecedented, to realize multi-band millimeter-wave integrated circuits.

Wide locking range frequency tripler based on a dual‐band VCO

A wide locking range (LR) injection locked frequency tripler (ILFT) based on a dual-band voltage controlled oscillator (VCO) is proposed in this Letter. By rationally designing the transformer parameters, the VCO can easily realise the adjacent dual-band operating characteristics. The ILFT has dual LRs which can easily overlap each other at a fixed bias. A subharmonic signal is also injected through the transformer for frequency locking. A wide LR of 27.1% from 69 to 90.6 GHz at an injection power of 0 dBm is achieved whereas the tripler only consumes 5.88 mW under a 0.6 V supply voltage.