Mid Band Research Articles

Eight Element Wideband Antenna with Improved Isolation for 5G Mid Band Applications

Eight Element Wideband Antenna with Improved Isolation for 5G Mid Band Applications

A dual ultra-wideband rectenna with a compact conical antenna for RF energy harvesting from S and C bands

The current research introduces a novel dual ultra-wideband rectenna that has been specifically devised for the S and C bands. The rectenna configuration being presented demonstrates the potential to efficiently capture energy from 1.5 GHz to 4.65 GHz, and 5.55 GHz–7.85 GHz. It is noteworthy to mention that the bandwidths (BW) corresponding to these frequency ranges are 3.15 GHz and 2.3 GHz, correspondingly. The envisioned rectenna is designed to cater to a selection of five distinct commercial bands. The frequencies under consideration include 1.8 GHz, UTMS 2.1 GHz, 5G 3.5 GHz, 4.5 GHz, and 5.8 GHz, which fall within the mid band range for 5G technology. Notably, the extended S-band and C band are also included within this range, catering specifically to 5G applications. For the purpose of rectification, a solitary HSMS 2850 Schottky diode has been selected. The maximum recorded Conversion Efficiency (CE) achieved at 1.8 GHz, 2.1 GHz, 3.5 GHz, 4.5 GHz, and 5.8 GHz corresponds to CE values of 67 %, 65 %, 77 %, 71 %, and 71 %, respectively. These CE measurements were obtained under varying input power levels (IPL) of −6 dBm, 4 dBm, 4 dBm, 2 dBm, and 9 dBm, respectively. The rectenna under consideration is designed to operate across five distinct frequency bands. Notably, the CE exceeds 65 % across all of these frequency bands. Consequently, the rectenna exhibits a higher output power. As a result, this modification makes it appropriate for supplying energy to low-power electronic equipment.

Survey and monitoring of ASKAP’s RFI environment and trends I: Flagging statistics

Abstract We present an initial analysis of Radio Frequency Interference (RFI) flagging statistics from archived Australian SKA Pathfinder (ASKAP) observations for the ‘Survey and Monitoring of ASKAP’s RFI environment and Trends’ (SMART) project. SMART is a two-part observatoryled project combining analysis of archived observations with a dedicated, comprehensive RFI survey. The survey component covers ASKAP’s full 700–1 800 MHz frequency range, including bands not typically used due to severe RFI. Observations are underway to capture a detailed snapshot of the ASKAP RFI environment over representative 24 h periods. In addition to this dedicated survey, we routinely archive and analyse flagging statistics for all scientific observations to monitor the observatory’s RFI environment in near real-time. We use the telescope itself as a very sensitive RFI monitor and directly assess the fraction of scientific observations impacted by RFI. To this end, flag tables are now automatically ingested and aggregated as part of routine ASKAP operations for all science observations, as a function of frequency and time. The data presented in this paper come from processing all archived data for several ASKAP Survey Science Projects (SSPs). We found that the average amount of flagging due to RFI across the routinely used ‘clean’ continuum science bands is 3%. The ‘clean’ mid band from 1 293 to 1 437 MHz (excluding the 144 MHz below 1293 MHz impacted by radionavigation-satellites which is discarded before processing) is the least affected by RFI, followed by the ‘clean’ low band from 742 to 1 085 MHz. ASKAP SSPs lose most of their data to the mobile service in the low band, aeronautical service in the mid band and satellite navigation service in the 1 510–1 797 MHz high band. We also show that for some of these services, the percentage of discarded data has been increasing year-on-year. SMART provides a unique opportunity to study ASKAP’s changing RFI environment, including understanding and updating the default flagging behaviour, inferring the suitability of and calibrating RFI monitoring equipment, monitoring spectrum management compliance in the Australian Radio Quiet Zone – Western Australia (ARQZWA), and informing the implementation of a suite of RFI mitigation techniques.

Modeling and Design of Nonresonant-Node-Based Filtenna for Triband Wi-Fi Application

The triband wireless Wi-Fi router radiated by series-fed antennas suffers from serious mutual coupling, resulting in throughput degradation. To reduce the mutual coupling, the filtering antennas (filtennas) are designed with nonresonant node (NRN) radiators and series-fed antennas. The NRN filtering radiators are characterized by the NRN filtering circuits, which includes the capacitance and inductance NRNs. These NRNs realize a parallel resonance and radiation zero simultaneously. The radiation zero frequency is smaller or larger than the resonant frequency in the capacitance and inductance NRN, respectively. As the mechanism to manipulate the resonant frequency and radiation zero is figured out, the NRN filtering radiators are designed, and the above analysis is validated. Then, the series-fed antenna equivalent to a parallel resonance is fed by the NRN filtering radiator, and a second-order bandpass filtering network is formed. Its filtering response with the radiation zero realizes a high out-of-band rejection to reduce the mutual coupling. For demonstration, a cross-coupling NRN filtenna is designed to work at 2.4–2.5 GHz low band (LB), while the inductance and capacitance NRN filtennas operate at 5.17–5.33GHz mid band (MB) and 5.735–5.835 GHz high band (HB), respectively. Herein, the radiation zero of the MB antenna is designed at HB, while the HB radiation zero operates at MB. The measurement results exhibit that the mutual coupling is reduced, and the throughput of the triband wireless Wi-Fi router is improved.

Optimizing dual-band antenna efficiency: Ridge width parametric study of quad ridge horn antennas

The purpose of this project was to develop a quad ridged horn antenna for a GSM and mid band 5G application, capable of dual frequency range operation at 1.8 GHz and 3.5 GHz. The antenna was constructed using 3D printing technology and Polylactic Acid (PLA), a thermoplastic polymer known for its high strength and compatibility with 3D printing processes. The impact of varying ridge width dimensions on the antenna's performance was evaluated using a range of parametric techniques. Ridge widths of 10 mm, 13.5 mm, and 17 mm were analysed to assess the effects of dimension alterations. Results demonstrated that the antenna is capable of dual band frequency operation with signal reflections of -16.89 dB and -28.60 dB at 1.8 GHz and 3.5 GHz, respectively. This research contributes to the development of efficient and cost-effective antennas for wireless communication applications in the GSM and mid band 5G spectrum.

Machine learning-based technique for gain and resonance prediction of mid band 5G Yagi antenna

In this study, we present our findings from investigating the use of a machine learning (ML) technique to improve the performance of Quasi-Yagi–Uda antennas operating in the n78 band for 5G applications. This research study investigates several techniques, such as simulation, measurement, and an RLC equivalent circuit model, to evaluate the performance of an antenna. In this investigation, the CST modelling tools are used to develop a high-gain, low-return-loss Yagi–Uda antenna for the 5G communication system. When considering the antenna’s operating frequency, its dimensions are {0.642}lambda _0times {0.583}lambda _0. The antenna has an operating frequency of 3.5 GHz, a return loss of -43.45 dB, a bandwidth of 520 MHz, a maximum gain of 6.57 dB, and an efficiency of almost 97%. The impedance analysis tools in CST Studio’s simulation and circuit design tools in Agilent ADS software are used to derive the antenna’s equivalent circuit (RLC). We use supervised regression ML method to create an accurate prediction of the frequency and gain of the antenna. Machine learning models can be evaluated using a variety of measures, including variance score, R square, mean square error, mean absolute error, root mean square error, and mean squared logarithmic error. Among the nine ML models, the prediction result of Linear Regression is superior to other ML models for resonant frequency prediction, and Gaussian Process Regression shows an extraordinary performance for gain prediction. R-square and var score represents the accuracy of the prediction, which is close to 99% for both frequency and gain prediction. Considering these factors, the antenna can be deemed an excellent choice for the n78 band of a 5G communication system.

A Jitter-Robust 40 Gb/s ADC-Based Multicarrier Receiver Front-End With 4-GS/s Baseband Pipeline-SAR ADCs in 22-nm FinFET

Demand for increased data rates in serial link transceivers calls for innovative architectures capable of overcoming impairments such as limited channel bandwidth (BW) and stringent jitter specifications. This article presents a receiver front-end (RXFE) architecture that supports multicarrier signaling to provide a ~3 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> relaxation in clock jitter requirements. A total of 40 Gb/s data rate is supported by three 4-GS/s bands with baseband (BB) four-level pulse amplitude modulation (PAM4) and mid-band (MB) and high-band (HB) 16-state quadrature amplitude modulation (QAM16) on 4- and 8-GHz orthogonal carriers, respectively. The RXFE uses three per-band optimized continuous-time linear equalizers (CTLEs) to partially equalize the in-band channel loss and four-way time-interleaved 7-b pipelined-successive approximation register (SAR) analog-to-digital converters (ADCs). Tight band spacing is achieved with tolerable inter-channel interference (ICI) using resettable integrators in the receiver segments. Fabricated in a 22-nm fin field-effect transistor (FinFET), the proposed 40-Gb/s multicarrier RXFE can tolerate up to 1.6-psrms jitter and achieve a bit error rate (BER) < 10−5 operating over a channel with 20-dB loss at 10 GHz when combined with an off-chip one-tap digital ICI canceller. The ADC-based front-end achieves 3.05-pJ/bit power efficiency, including all the front-ends, ADC, and clocking power.

A Reconfigurable Octa-Band Antenna with a High Gain for a Variety of Wireless Applications

The Octa-band frequency reconfigurable antenna proposed in this paper can operate in the UWB, GSM, WiMax, 5G MID BAND, WLAN (C-BAND), WLAN (S-BAND), 5G (C-BAND), and STM link-1 bands. To achieve the desired operating frequency, the ground plane of the UWB monopole antenna is modified by embedding two inverted L-shape slots. A novel frequency selective surface (FSS) reflector consisting of a 5 × 5 array of elements is located at a distance of 0.78λ at 6.2 GHz below the proposed reconfigurable antenna to improve its gain. The addition of FSS resulted in a gain improvement of 3–7 dBi. The proposed antenna has a wide switching capability, allowing it to be integrated into portable electronic devices and making it suitable for 5G and other wireless applications.

Antennas for Licensed Shared Access in 5G Communications with LTE Mid- and High-Band Coverage.

Two novel antennas are presented for mobile devices to enable them to access both licensed shared access (LSA) bands (1452-1492 and 2300-2400 MHz) and all the long-term evolution (LTE) mid (1427-2690 MHz) and high (3400-3800 MHz) bands, together with the GSM1800, GSM1900, UMTS, and 3.3 GHz WiMAX bands. These antennas do not require any passive or active lumped elements for input impedance matching. One of them is a dual-band antenna and the other is a wideband antenna. Both antennas have high efficiency in all the LSA bands, as well as the mid- and high-LTE bands, and nearly omnidirectional radiation patterns in the mid band. In the high band, the radiation patterns of the wideband antenna are less directional than those of the dual-band antenna. The wideband antenna was fabricated and tested and the measurements demonstrated that it had good wideband performance in a wide frequency range from 1.37 to 4 GHz, covering all the above-mentioned bands.

Continuously broken ergodicity and reversible photo-darkening in As-Ch glass

The exact mechanism responsible for reversible photo-darkening in As-Ch glasses has been an open question. Many mechanisms have been suggested. Here I assume that self trapped excitons (STE) cause a local structural relaxation and end up in mid band states. I show that such an excitonic state produces a local frustration field which distorts the lattice. These states most probably decay non-radiatively through excitation of localized modes satisfying quantum statistics. I posit that these localized modes are the result of continuously broken ergodicity. These modes can channel to form local oscillations, which would act to raise the temperature, or couple to the valence electronic energy, which results in a local structural modification. I show the observed temperature dependence of both the band edge shift and the volume increase are predicted by the latter mechanism.

The Rapid ASKAP Continuum Survey IV: continuum imaging at 1367.5 MHz and the first data release of RACS-mid

Abstract The Australian SKA Pathfinder (ASKAP) is being used to undertake a campaign to rapidly survey the sky in three frequency bands across its operational spectral range. The first pass of the Rapid ASKAP Continuum Survey (RACS) at 887.5 MHz in the low band has already been completed, with images, visibility datasets, and catalogues made available to the wider astronomical community through the CSIRO ASKAP Science Data Archive (CASDA). This work presents details of the second observing pass in the mid band at 1367.5 MHz, RACS-mid, and associated data release comprising images and visibility datasets covering the whole sky south of $\delta_{\text{J2000}}=+49^\circ$ . This data release incorporates selective peeling to reduce artefacts around bright sources, as well as accurately modelled primary beam responses. The Stokes I images reach a median noise of 198 $\mu$ Jy PSF $^{-1}$ with a declination-dependent angular resolution of 8.1–47.5 arcsec that fills a niche in the existing ecosystem of large-area astronomical surveys. We also supply Stokes V images after application of a widefield leakage correction, with a median noise of 165 $\mu$ Jy PSF $^{-1}$ . We find the residual leakage of Stokes I into V to be $\lesssim 0.9$ – $2.4$ % over the survey. This initial RACS-mid data release will be complemented by a future release comprising catalogues of the survey region. As with other RACS data releases, data products from this release will be made available through CASDA.

Triple-band stub loaded patch antenna with high gain for 5G Sub-6 GHz, WLAN and WiMAX applications using DGS

Microstrip antennas have become ubiquitous in today's wireless communication world due to their low profile, low cost, and simplicity in fabricating on circuit boards. However, poor performance characteristics, such as limited bandwidth, low power handling capabilities, and low gain, limit their applicability in various instances. Path loss will be substantial in 5th generation (5G) wireless communication due to the utilization of high-frequency bands. A high-gain antenna with a small size is necessary to address this issue. A compact tri-band, slotted monopole antenna with high and consistent gain employing a defected ground plane structure (DGS) has been investigated and implemented in this study. This proposed antenna uses three inverted L-shaped stubs connected to the radiating element to cover the desired bands while keeping the antenna size small. The designed antenna has two key characteristics: (i) wide bandwidth and (ii) reasonable gain. The antenna covers 2.45 and 5.6 GHz WLAN, 2.4 GHz Wi-Fi, 2.5 and 5.2 GHz WiMAX and 3.7 GHz Sub-6 GHz of 5G for mobile communication. The overall substrate size of the antenna is 30 ? 17 ? 1.6 mm3and the electrical dimensions are 0.49 ?L ? 0.28 ?L ? 0.026 ?L, where ?L is the free space wavelength at 2.45 GHz. The measured reflection coefficient (S11 &lt; -10dB) covers 2.4 - 2.52 GHz (bandwidth 112 MHz) and 3.4 - 4.1 GHz (bandwidth 700 MHz) and 5.2 - 6.6 GHz (bandwidth 1359 MHz) with a fractional bandwidth of 5.1 % at lower frequency band, 18.6 % at mid frequency band and 23.7 % at high frequency band. A prototype antenna has also been developed using an inexpensive, low-profile 1.6 mm thick FR-4 (?r = 4.4) substrate. The measured peak gains achieved are 1.35 dB at 2.45 GHz, 2.55 dB at 2.65 GHz and 3.8 dB at 5.5 GHz. The simulated results have been validated against actual experimental measurements, and the outcomes are consistent and match with certainty. The proposed antenna design is very compact and easy to fabricate due to the absence of vias.

Design and Analysis of a 4-port MIMO Microstrip Patch Antenna for 5G Mid Band Applications

Design and Analysis of a 4-port MIMO Microstrip Patch Antenna for 5G Mid Band Applications

Role of defect states in hopping transport and photoconductivity properties of WSe2-FeS2 nanocomposite thin films

Transition metal dichalcogenides (TMDs) are one of the promising materials in the field of electronics and optoelectronics. The multifunctional TMD based nanocomposites such as WSe 2 -FeS 2 can also become a potential candidate for these applications. In this work, WSe 2 -FeS 2 nanocomposite thin films have been fabricated and studied for electrical transport and photoconductivity studies for the first time. Structural and optical analysis has been done, probing nanocomposite formation and defect states present in the deposited film. XPS analysis of WSe 2 -FeS 2 shows solid interfacial bonding in the deposited films. Raman analysis shows the presence of E 1 2 g mode for WSe 2 and E g , A g , T g modes for FeS 2 and shift in Raman peaks corresponds to the disorder in the film. Also, the blue (red) shift of FeS 2 (WSe 2 ) PL emission probes the presence of defect/trap states. Temperature-dependent (173–350 K) resistivity results reveal the presence of more than one type of carrier transport mechanism - thermally activated conduction and hopping transport. The chalcogenide vacancies in WSe 2 -FeS 2 affect the formation of trap states responsible for forming localized states. These localized states play a crucial role in the variable range hopping conduction at low temperatures. Whereas photoconductivity study yields a non-significant effect of light on photocurrent due to entrapment of carriers in trap states up to 250 K. Afterwards, a significant photocurrent increase was observed. The detailed mechanism considering all these aspects is explained in this work. It provides substantial new understandings for the carrier transport in WSe 2 -FeS 2 nanocomposite thin films. • Structural, morphological and optical analysis of WSe 2 - FeS 2 nanocomposite thin films. • Temperature dependent carrier transport studies by thermally activated and hopping conduction mechanism. • Persistent photoconductivity in WSe 2 - FeS 2 nanocomposite film due to entrapment of carriers in mid band gap trap states.

High photocatalytic activity of aerogel tetragonal and monoclinic ZrO2 samples

ZrO2 nanoparticles have been investigated in the photodegradation of formic acid under UV irradiation. ZrO2 photocatalysts were prepared using a ‘one-pot’ sol-gel method followed by drying under supercritical conditions of solvent and calcination at temperatures varying between 400 °C and 800 °C. Samples were characterized by adsorption-desorption isotherms, XRD, Thermal analysis, Raman spectroscopy, HRTEM, DRS, PL and XPS. The aerogel preparation allows the creation of intermediate band gap states making it active under UV irradiation. The photoactivity of ZrO2 samples follow the order; ZrO2 400 ≥ ZrO2 800 > ZrO2 700 > ZrO2 500 > ZrO2 600 in agreement with their optical properties. The lower the value of mid band gap, the higher the photocatalytic activity. The value of mid band gap depends on the nature of the ZrO2 phase (tetragonal or monoclinic), surface oxygen defects and the tendency to lattice distortion for samples treated at high temperature. This study therefore shows for the first time that adequate preparation of oxide materials (here ZrO2) allows finely tuning the creation of intermediary band gap sites through thermal post-treatments making ZrO2, a large band gap material, able to photocatalytically work under UV irradiation.

Design of a 0.5–18 GHz Wideband Frequency Down-Converter Module with a Local Circuit for an Electronic Support Measurement System

In this paper, we describe the design and fabrication of a wideband frequency down converter module that has a local circuit with high gain, low spurious, high IP3 (3rd intercept point) characteristics, and reliability; this is accomplished by applying a chip-and-wire process using a bare type monolithic microwave integrated circuit (MMIC) device. To compensate for the mismatch among many sub-modules, an input module, filter bank module, output module, and local oscillator (LO) module suitable for sub-band frequency characteristics were designed and applied to the down converter. Th e frequency down converter module had three paths: 0.5−2 GHz (direct), 2−6 GHz (direct), and 6−18 GHz (converter). Amplitude-matched radio frequency (RF) semi-rigid cables of different lengths were used to connect to the internal sub-modules of the frequency down converter. The main RF line was a dielectric substrate, RT/duroid 5880, with a relative dielectric constant of 2.2 and a dielectric thickness of 0.127 mm. In the wideband frequency down converter module, the gain was 22.7 dB at low band (input frequency, 0.5−2 GHz) with a flatness of about 3.4 dB. Th e gain was 22.6 dB at mid band (input frequency, 2−6 GHz) having flatness about 2.0 dB. The gain was from 30 dB at edge frequency of high band (input frequency, 14−18 GHz) with a flatness of about 4.2 dB. The measured value of IP3 at LB was +23.52 dBm, +25.66 dBm and +23.44 dBm as the maximum value. The measured value of spurious (LO-2IF) at the converter path was 34.97 dBc as the maximum value.

Printed monopole antenna design with CPW fed for ultra wideband application

A circular monopole antenna fed by co-planar waveguide(CPW) for ultra wideband application is described in this article. The usage of a co-planar ground plane help to increase bandwidth for a frequency range 5G frequency spectrum’s mid band. The proposed antenna is designed to operate from 4.8GHz to 14.10GHz. With this proposed antenna, a suitable omnidirectional radiation pattern can be created. Comparison of fractional bandwidth value for various gap between the ground plane and the patch for satisfying the criteria for UWB has been analysed here.

Similarities and differences in accretion flow properties between GRS 1915+105 and IGR J17091-3624: A case study

We perform a comparative spectro-temporal analysis on the variability classes of GRS 1915+105 and IGR J17091-3624 to draw inferences regarding the underlying accretion flow mechanism. The ν, as well as C2 class Rossi X-ray Timing Explorer observation, have been considered for analysis. We investigate the intensity variation of the source in different energy domains that correspond to different components of the accretion flow and infer the relative dominance of these flow components during the dip/flare events. We correlate the dependence of the dynamic photon index (Θ) with intensities in different energy bands and comment on the transition of the source to hard/soft phases during soft dips/flares. We also report the presence of sharp QPOs at ∼7.1 Hz corresponding to both softer and harder domain in the case of ν variability class of GRS 1915+105 and discuss the possible accretion flow configuration it suggests. Sharp QPO around ∼20 mHz is observed in ν and C2 classes of IGR J17091-3624 in low and mid energy band (2.0–6.0 keV and 6.0–15.0 keV), but remains undetected in high energy (15.0–60.0 keV). The 2.5–25.0 keV background-subtracted spectra have also been fitted with TCAF along with a Compton reflection component. A plausible accretion flow mechanism in order to explain the observed variability has been proposed.

Forecasts on interacting dark energy from the 21-cm angular power spectrum with BINGO and SKA observations

ABSTRACT Neutral hydrogen (H i) intensity mapping is a promising technique to probe the large-scale structure of the Universe, improving our understanding of the late-time accelerated expansion. In this work, we first scrutinize how an alternative cosmology, interacting dark energy (IDE), can affect the 21-cm angular power spectrum relative to the concordance ΛCDM model. We re-derive the 21-cm brightness temperature fluctuation in the context of such an interaction and uncover an extra new contribution. Then we estimate the noise level of three upcoming H i intensity mapping surveys, namely Baryon Acoustic Oscillations from Integrated Neutral Gas Observations (BINGO), Square Kilometre Array (SKA1)-MID Band 1 and Band 2, and employ a Fisher matrix approach to forecast their constraints on the IDE model. We find that while Planck 2018 maintains its dominion over early-Universe parameter constraints, BINGO and SKA1-MID Band 2 provide complementary bounding to the latest cosmic microwave background measurements on the dark energy equation of state w, the interacting strength λi and the reduced Hubble constant h, and that SKA1-MID Band 1 even outperforms Planck 2018 in these late-Universe parameter constraints. The expected minimum uncertainties are given by SKA1-MID Band 1 + Planck: $\sim 0.34{{\ \rm per\ cent}}$ on w, $\sim 0.22{{\ \rm per\ cent}}$ on h, $\sim 0.64{{\ \rm per\ cent}}$ on H i bias bHi, and an absolute uncertainty of about 3 × 10−4 (7 × 10−4) on λ1 (λ2). Moreover, we quantify the effects from systematics of the redshift bin number, redshift-space distortions, foreground residuals and uncertainties on the measured H i fraction, ΩHi(z). Our results indicate a bright prospect for H i intensity mapping surveys in constraining IDE, whether on their own or by synergies with other measurements.

Optimized Bandwidth Enhanced Wideband Microstrip Antenna for 5G Applications

In this article, a single port with truncated corner and common T-shaped notch loaded microstrip patch antenna for bandwidth enhancement is presented which is useable for mid band of 5G applications. The design of this prototyped antenna is obtained by loading truncated corner and T-shaped notch on rectangular patch antenna having 50 Ω microstrip line feed. The optimized antenna 5 is selected as proposed antenna at design frequency 3 GHz among antenna 1- antenna 5after study of simulated results through IE3D Mentor Graphics simulation software. Proposed antenna covers a wide bandwidth from 2.39 to 4.04 GHz and fractional bandwidth of 51.3% with pair of resonance frequency having return loss of -23.38 dB and -29.65 dB respectively.