Dual-band Configuration Research Articles

EARTHEN LAMP-SHAPED DGS DUAL BAND MICROSTRIP PATCH ANTENNA FOR HIGH RETURN LOSS IN BIOMEDICAL APPLICATION

This study illustrates a dual-band circular and pentagon antenna with dual-band configuration for the high return loss. When an antenna has a greater return loss, less power is reflected toward the transmitter, implying that the antenna and transmission line are better suited. Due to its accessibility, the FR4 substrate is used to replicate the design. With a bandwidth of 150 MHz and 200 MHz, respectively, the antenna's dual-band performance is between 2.32 GHz to 2.47 GHz and 2.9 GHz to 3.1 GHz. The body phantom design in CST Studio is used to test the design's biocompatibility. It is demonstrated by the improved antenna in the industrial, scientific, and medical (ISM) band region that it can be utilized for telemetry or medical services.

High PAE CMOS Power Amplifier With 44.4% FBW Using Superimposed Dual-Band Configuration and DGS Inductors

A two-stage 180-nm CMOS wideband (14–22 GHz) power amplifier (PA) with a superimposed staggered technique and defected-ground-structure (DGS) inductors is introduced, where a wideband peaking main stage is designed at the center frequency; then, a superimposed dual-band (SDB) driver stage is proposed to obtain the optimally flat gain response over the whole bandwidth (BW). Also, DGS inductors are used to enhance the power added efficiency (PAE) of the implemented PA by decreasing the matching circuits’ insertion losses. The proposed PA achieved a power gain of 12 dB at a total chip area of 0.564 mm2. Also, at the center frequency, it achieved a saturated output power of 16.6 dBm exhibiting the smallest reported amplitude-to-phase (AM-PM) distortion (2.1°) and group delay (GD) variations (±66 ps). Finally, it gives among the highest fractional bandwidth (FBW) (44.4%) and the PAE (18.7%) so far. Also, it achieves an error vector magnitude of −25 dB at 9.3-dBm output power for a 400-MHz 5G-NR signal.

Dual-Band X-Shaped Absorber Design for Sensor Applications

This study presents a compact absorber design with an X-shaped resonator (XSR) in the S-band region. The proposed design offers single or dual-band absorption peaks, depending on whether the arm lengths of the resonator are symmetrical or asymmetrical. Prototype fabrications of the absorber, whose numerical design was carried out using CST Microwave Studio, were also measured for verification. Based on the simulated and measured results, the proposed absorber exhibited over 93% absorption spectra with relatively narrow bandwidth characteristics desired, especially for sensor applications. It also provided cross-polarized reflections of less than 0.08 at the frequencies of interest. In addition, the absorption frequency changes depending on the dielectric constant and thickness variations of the sensing layer placed on the absorber were obtained numerically and experimentally to investigate the sensing performance of a dual-band configuration of the absorber. In addition, the same analyzes and measurements were carried out again for two separate single-band split-ring resonator (SRR)-based absorbers designed in this study, and their sensing performances were compared with the dual-band X-shaped absorber's performance. As a result, it was found that the proposed X-shape absorber was more sensitive than the SRR-based absorber, considering the comparison results.

High-Efficiency Reconfigurable Dual-Band Class-F Power Amplifier With Harmonic Control Network Using MEMS

This letter presents a novel reconfigurable, high-efficiency class-F power amplifier (PA) structure, using a commercial GaN-HEMT, that achieves dual-band configuration not only at the fundamental frequency but also at the harmonics. With a proper harmonic tuning structure, the need for an extra filtering section is eliminated, resulting in a high dual-band efficiency with a reduced number of components and size. The reconfigurable structure uses commercial single-pole-double-throw (SPDT) and single-pole-single-throw (SPST) MEMS switches optimally placed on the stubs to select between 900 and 1800 MHz. The reconfigurable PA achieves a measured power-added efficiency (PAE) of 69.5% and a power gain of 13.6 dB while delivering an output power of 39.1 dBm at 900 MHz. At 1800 MHz, the amplifier achieves a PAE of 57.9%, a power gain of 10.5 dB, and an output power of 38.5 dBm.

A Single-Layer Dual-Band Reflectarray Cell for 5G Communication Systems

A single-layer dual-band reflectarray cell is proposed in this work for future 5G systems. A reflectarray unit cell operating at 28/38 GHz is designed by adopting two pairs of miniaturized fractal patches, offering low losses (<0.7 dB) and almost full-phase ranges (≅320°) at both operating frequencies. The proposed configuration allows to achieve very small interelement spacings and negligible mutual coupling effects between the two bands, thus assuring an independent phase-tuning mechanism at both desired frequency bands. The designed compact cell is successfully adopted to demonstrate reflectarrays’ abilities in achieving fixed scanned-beam and/or multibeam patterns, under the dual-band operation mode. Full-wave numerical validations, performed on the synthesized reflectarray structures, confirm the effectiveness of the designed dual-band configuration in achieving independent radiation patterns and quite good bandwidths, at the two designed frequencies. Thanks to its compactness and versatility in achieving both frequency diversity and multibeam/scanned-beam radiation patterns, the proposed unit cell is appealing for future 5G applications.

Optical receiver sensitivity enhancement by single- and dual-band fiber optical parametric amplifier.

A semi-classical model is proposed theoretically and demonstrated experimentally on the optical receiver sensitivity enhancement by single-band (signal or idler) and dual-band (signal and idler) fiber optical parametric amplifier (FOPA). The sensitivity enhancement by single-band is determined by the gain of FOPA and the transmission loss of signal and idler, and it can be further improved by up to 3-dB using amplified signal and phase-conjugated idler together at dual-band configuration. The theoretical results are experimentally verified in both fiber communication and biomedical imaging applications. This detection sensitivity enhancement scheme can be potentially applied in the scenarios where ultrafast broadband signal at low-power level is being handled.

The EMIR multi-band mm-wave receiver for the IRAM 30-m telescope

Aims. The prime motivation of this project was to design and build a state-of-art mm-wave heterodyne receiver system to enhance the observing throughput of the IRAM 30-m radiotelescope. More specifically, the requirements were i) state-of-art noise performance for spectroscopic observations; ii) simultaneous dual polarization and dual-frequency observing; iii) coverage of the atmospheric transmission windows from 83 to 360 GHz; iv) compact footprint and minimal maintenance.Methods. Key elements for low noise performance of heterodyne mixers are the superconducting Niobium junctions, operating at ≃4 K. These junctions are embedded in carefully designed coupling structures; furthermore, since atmospheric radiation is a significant contributor to the system noise budget, all mixers are either sideband separating or sideband rejecting. To achieve low noise, it is also essential to maximize the coupling of the receiver to the astronomical source, and to minimize the coupling to thermal radiation from the ground-based environment; this is achieved through mirror optics that realize a wavelength-independent coupling to the telescope. A flexible configuration of mirrors and frequency selective surfaces permits various combinations of frequency bands, as well as dual-load radiometric calibration. Low noise intermediate frequency amplifiers and bias electronics also play an important role in the system performance.Results. The EMIR receiver in operation at the 30 m telescope offers four frequency bands: B1: 83−117 GHz, B2: 129−174 GHz, B3: 200−267 GHz, and B4: 260−360 GHz. In each band, the two orthogonal polarizations are observed simultaneously. Dual-band combinations B1/2 B1/3, and B2/4 are available. Bands 1 and 4 (also 3 as of Nov.-2011) feature sideband separation. In dual-band configuration, including sideband separation and polarization diplexing, up to eight IF channels are delivered to the spectrometers, totaling up to 64 GHz of signal bandwidth (of which 32 GHz can be transported and processed by spectrometers, status Nov.-2011). The EMIR receiver has been in continuous operation for more than two years and has allowed, through a qualitative jump in performance, observations not possible before, as shown by a few selected examples of astronomical results.

Dual-Band Stimulated Parametric Emission Microscopy

We demonstrate that two distinct images can be simultaneously acquired using the dual-band configuration of stimulated parametric emission (SPE) microscopy, which is based on the four-wave mixing process enhanced by two-photon electronic resonance. The dual-band SPE microscopy utilizes two SPE signals simultaneously generated at different wavelengths. In the experiment, we image stained and unstained biological tissues, and obtain two different images for each sample. Additionally, we propose an axial differential imaging technique to improve the contrast of SPE images, and verify its applicability to biological imaging.

A Non-Coherent DPSK Data Receiver With Interference Cancellation for Dual-Band Transcutaneous Telemetries

A dual-band telemetry, which has different carrier frequencies for power and data signals, is used to maximize both power transfer efficiency and data rate for transcutaneous implants. However, in such a system, the power signal interferes with the data transmission due to the multiple magnetic couplings paths within the inductive coils. Since the power level of the transmitted power signal is significantly larger than that of the data signal, it usually requires a high-order filter to suppress the interference. This paper presents a non-coherent DPSK receiver without a high-order filter that is robust to the interference caused by the power carrier signal. The proposed scheme uses differential demodulation in the analog domain to cancel the interference signal for a dual-band configuration. The data demodulation also uses subsampling to avoid carrier synchronization circuits such as PLLs. The experimental results show that the demodulator can recover 1 and 2 Mb/s data rates at a 20 MHz carrier frequency, and it is able to cancel an interference signal that is 12 dB larger than the data signal without using complex filters. The demodulator is fabricated in a 0.35 mum CMOS process, with a power consumption of 6.2 mW and an active die area of 2.6times1.7mm2.

Analysis of a Dual-Band Dual Slot Omnidirectional Stripline Antenna

In this letter, measured and simulated results for a dual-band dual slot omnidirectional stripline antenna are presented. This particular dual slot configuration allows tuning of two resonant frequencies, where simulated results obtained using an in-house FDTD computer program agreed well with measured results. The symmetrical dual-band configuration radiates equally on both sides of the substrate and provides a reasonable 10 dB bandwidth of 25% at 5.8 GHz and 10% at 2.45 GHz

Simultaneous Dual Band Transmission Over Multimode Fiber-Fed Indoor Wireless Network

Performance measurements of different combinations of digital enhanced cordless telecommunications packet radio service, global system for mobile communications, universal mobile telecommunication service, and 802.11g (54 Mbps) signals in a dual band configuration transmitted over an indoor wireless network fed by a low-cost 850-nm vertical-cavity surface-emitting laser (VCSEL)-300m multimode fiber link are presented. The feasibility of such a system is demonstrated with error vector magnitude measurements which are within the required specifications.

Multilayer multiresonator circular microstrip antennas for broadband and dual-band operations

Different methods to increase the bandwidth of a microstrip antenna, such as use of an air-gap in-between stacked resonators and the ground plane and planar multiresonators, are combined to achieve broad bandwidth with increased gain. A configuration with two gap-coupled circular microstrip antennas on the top dielectric layer stacked with one coaxial-fed circular patch on the bottom layer and an air-gap in-between two layers and the ground plane yield a bandwidth of 1093 MHz (47%) with a gain of 9.54 dB at the S-band frequency of 2.325 GHz. Also, dual-band response with broadside radiation and improved gain at both frequencies is achieved by suitably changing parameters of this configuration. Parametric studies of this configuration on dielectric substrate for both broadband and dual-band operation are presented in this paper. The experiments are performed on broadband and dual-band configurations, which are in agreement with the theoretical results. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 489–494, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21208

Mirror antenna dual-band lightweight mirror design

The mirror antenna, sometimes called an inverse Cassegrain antenna, is used in modern radar systems where efficient wide angle scan is required in combination with light weight and small size. Although previous applications have been single band, an additional advantage of the mirror antenna is that it is practical to implement dual-band configurations which can greatly enhance the capability of radar or other radiating systems. The most difficult part of a dual-band mirror antenna design is the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">90\deg</tex> polarization rotating mirror (half-wave plate). The challenge is to achieve effective performance at two bands and maintain that performance over a wide range of aspect angle. Basic mirror antenna operation and design and fabrication techniques for a dual-band half-wave plate mirror are described. The solution for design parameters is derived for perfect <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">90\deg</tex> polarization rotation at a given aspect angle for each of the two bands. The design approach includes a process for optimizing the design for the full desired range of aspect angles. Practical fabrication considerations are discussed along with inclusion of the effects of capacitive susceptance of a protective mirror coating in the design theory. Theoretical performance is compared with measurements of mirror samples.