Frequency Band Applications Research Articles

A novel approach for low mutual coupling and ultra-compact Two Port MIMO antenna development for UWB wireless application

In this paper, a novel MIMO antenna operating in the UWB frequency band is presented. The proposed new antenna shape is derived from the conventional circular ring patch antenna having a partial ground plane. An array of three Quad-G Shaped Metamaterial structures was used between the antenna elements of the two-port MIMO antenna to expand the bandwidth in the lower frequency band of UWB application (below 5.567 GHz) and reduce the mutual coupling in such expanded band. The proposed MIMO antenna operates over a bandwidth of 8GHz from 4 GHz to 12 GHz. Over the entire bandwidth, the mutual coupling between antenna elements is less than -19.0 dB with an inter-element separation (sep) of λ/6 mm. The overall optimized dimensions of the proposed antenna are 0.34λ×0.22λ×0.021λ for a free-space wavelength, λ, calculated at 4GHz. The radiation pattern of the proposed MIMO antenna was analyzed using the Combined Results Technique (CRT) integrated into the CST microwave studio. The obtained peak radiation efficiency and gain are 83.0% and 5.57 dB respectively. The MIMO Performance metrics such as envelope correlation coefficient (ECC), diversity gain (DG), channel capacity loss (CCL), Mean Effective Gain (MEG), Total Active reflection Coefficient (TARC), and multiplexing efficiency are evaluated and compared to the standard values. The proposed antenna was compared to other antennas in the literature. It has been found that the key benefit of the present method was observed in achieving the highly miniaturized overall antenna dimension having good MIMO system performance metrics and better radiation characteristics. The proposed antenna was fabricated and measured. The measured and simulated values are found to be in good agreement.

Design of a 3-way wide-band in-phase power combiner for UHF applications

ABSTRACT In this work, a three-way wide-band in-phase power combiner for ultra-high frequency band (UHF) applications is presented. The proposed power combiner is a modification of the conventional 3-way Wilkinson power combiner. In the proposed power combiner, the floating isolation-resistors are replaced by coaxial baluns and 50-Ω terminations. This configuration is suitable for high-power applications as flange-mount terminations exhibit superior frequency response and heat conduction compared to floating resistors. The coaxial baluns, connected in the star configuration, help for isolation and input-ports matching. The characteristic impedance of coaxial baluns is 50-Ω and is matched to the terminations. This property serves for a broad bandwidth. Even- and odd-mode methods are employed for the analysis and design of the power combiner. To validate the design method and the theoretical results, a three-way power combiner is fabricated, which consists of microstrip, coaxial-cables and some 50-Ω terminations. The combiner provides 20-dB isolation and summing-port return-loss over an octave bandwidth. The operating frequency is between 470 and 860 MHz, which is used for digital video broadcasting–terrestrial (DVB-T).

Ultra-Wideband Annular Ring Fed Rectangular Dielectric Resonator Antenna for Millimeter Wave 5G Applications

In this article an ultra-wideband rectangular Dielectric Resonator Antenna is designed for millimeter wave 5G frequency band applications. Indoor 5G communications require antenna system with wide bandwidth and high efficiency to enhance the throughput in the channel. To fulfill such requirements a Dielectric Resonator Antenna (DRA) is designed here which has achieved an ultra-wide bandwidth of 20.15% (22.32–27.56 GHz) which is 5.24 GHz of bandwidth centered at 26 GHz as resonating frequency. This covers the complete band 30 (24.3–27.5 GHz) of 5G spectrum. 26 and 28 GHz are considered as most popular frequencies in millimeter wave 5G communications. The aperture fed DRA designed here has also achieved an efficiency of 96 percentage with maximum radiation in the broadside direction (Phi = 0, Theta = 0). The measured gain of the DRA is 6.3 dB. The DRA designed here has dimensions of 0.25 λ0×0.22 λ0×0.12 λ0. under the characteristic's mode. The DRA is placed over a substrate with dimensions 0.5 λ0×0.5 λ0×0.02 λ0. A cross slot aperture has been made on the ground plane which is placed above to the substrate. Here a full ground plane is used to resonate the antenna and is of similar dimension to the substrate. A microstrip line with two concentric rings makes an annular feed structure is used to excite the DRA and is placed below the substrate. The DRA is excited here in characteristics mode TE1Y1 and is the only mode of excitation. The DRA is linearly polarized, and the characteristic mode of excitation is maintained with 50 Ohm input impedance of the antenna. The DRA also gives here a good difference between the co-pol and cross pol approximately 15 to 20 dB. This antenna is more suitable for 5G indoor applications in millimeter wave frequency band centered at 26 GHz.

Extra Wide Band MIMO Antenna with High Isolation and Low Correlation at 38 GHz mm-Wave Frequency Band for 5G Applications

A compact wide-band Multiple Input Multiple Output (MIMO) antenna having highest isolation and least correlation for millimeter-wave 5G communications is proposed in this paper. Firstly, a single antenna was designed and simulated to be working at 38 GHz, a potential target band for 5G applications. It consists of a 5-shaped radiating patch, with partial ground plane. Its length is adjusted and a wide bandwidth is obtained. Then, the two antenna elements are closely positioned with edge-to-edge spacing of 1 mm (0.55 λ, with λ is the free space wavelength at resonance). Thanks to the technique of spatial diversity, a high degree of isolation is attained; more than 25 dB in the whole bandwidth. Moreover, correlation value is under 0.0002 in the working band. The prototype antennas are fabricated and measured. The result indicates that this antenna shows a reflection coefficient under -10 dB over a range of frequencies from 32.3 to 54.6 GHz (BW=22.3 GHz, 58.68% fractional bandwidth). The antenna presents a high realized gain of 7.12 dBi and radiation efficiency of about 82.46% at the desired frequency. Due to these results, our antenna may be regarded a suitable candidate for mm-wave 5G MIMO applications.

RF self-interference canceller prototype for 100-W full-duplex operation at 225–400 MHz

Military applications require more and different characteristics from in-band full-duplex radio technology than what the research prototypes developed for civil/commercial applications can offer. While the challenge of cancelling the strong transmit–receive coupling, i.e., self-interference (SI), in a full-duplex radio has been largely resolved at higher ultra high frequency (UHF) bands for low-power transmission, tactical communication and electronic warfare applications require major research efforts toward supporting lower military-relevant frequencies and significantly higher transmission power levels. In this paper, we present a prototype of a radio-frequency SI cancellation circuit for the lower UHF band at 225–400 MHz and transmit power of up to 100–200 W. The experimental results demonstrate that the canceller can suppress SI by 40–50 dB depending on the operation frequency within the band. It is targeted for the military application of simultaneous full-duplex jamming and interception of communications, where we can estimate that a 5-W signal-of-interest could be intercepted from 10 km away when simultaneously jamming with 100 W power.

Silver nanoparticle inkjet-printed multiband antenna on synthetic paper material for flexible devices

Flexible inkjet-printed antenna is presented. The proposed antenna is designed on a synthetic paper substrate with an area of 35 × 40 mm2 to provide frequency bands for many popular wireless applications. Simulation and measurement are used to study the performances, including the frequency bands, radiation patterns, peak gains and efficiency, of the antenna in two severely bending conditions with a curvature radius of 20 mm in the forward and backward directions. The antenna printed in photo papers material could not be fully flexible due to cracks introduced to the coating material on the surface of the photo paper. Hence, the resin coated material was only suitable for curved devices. The synthetic paper material used in this paper does not have a resin coating, therefore, the antenna does not lose its flexibility and can be bent in both the forward and backward directions without any cracks. Results show that bending in these two conditions has insignificant effects on the performances of the antenna. With a curvature radius of 20 mm in the forward direction, the measured peak gain and efficiency of the antenna are in the ranges from −3 to +2 dBi and 40% to 60%, respectively. The results together with the low cost make the antenna most suitable for many flexible 5G communications devices.

A Comparison of Wireless Devices for Terahertz Imaging Applications

As technology advances, notable scientific research accomplishments have been made. Terahertz (THz) waves have been seen to have endless potential applications that could further improve the current limitations of other frequency bands for imaging applications. Currently, THz waves display great potential in various applications due to their noninvasive and nonionizing features. However, the THz band has not been technically well established. This paper focuses on a comparative survey of the current methods applied in THz imaging in the field of medical and industrial security applications. Different types of methods, findings, advantages, and challenges of surveys ranging from 2016 to 2021 were discussed for both medical and industrial security applications to deepen the understanding of the latest trends, research, and technologies to have efficient THz imaging systems.

A Hybrid Antenna with Equal Beamwidth in Two Frequency Bands for Radar Applications

This paper presents a novel hybrid antenna with equal beamwidth in two frequency bands for short-range radar applications. The proposed design consists of a 2 × 2 patch array and a SIW-fed dielectric rod antenna. The two kinds of radiators are responsible for the 5.8 GHz and 24 GHz ISM bands, respectively. Pencil beams are obtained in both lower and upper bands. The beamwidth generated by the dielectric rod can be flexibly tuned to coincide with that of the patch array. Magneto-electric (ME) dipole, composed of a slot and two parasitic monopoles, is constructed to replace the conventional 3-D waveguide feeder, which can excite the dielectric rod effectively. The complementary structure is helpful to obtain a pencil beam. The 2 × 2 patch array has the size of 70 × 70 mm2 and is fed by a four-way power divider. Due to no overlapping radiating aperture, the two radiators can work independently with high port isolation. The measured peak gain in the two bands is 12.5 dBi and 12.7 dBi. The measured 3-dB beamwidth at 5.8 GHz and 24 GHz is 42° and 39° in x-z plane, and 43° and 42° in the y-z plane. The proposed antenna features a small beamwidth difference in two frequency bands, thus being attractive for dual-band radar systems.

Design of miniaturized dual-polarized dipole antenna for 4G & sub-6 GHz 5G applications

Abstract Dual-polarization, enhanced gain and compact size is the basic need of the base station antennas whereas a modern communication system needs a wideband antenna which can cover both the LTE & 5G applications. In the present work, a cross dipole antenna is proposed for LTE & sub 6 GHz 5G frequency band for Base Station Antenna Applications. By introducing asymmetrically shaped pentagon slots in the dipole and open-loop dipole patches, wide impedance bandwidth of 1.65–4.05 GHz at a return loss of −14 dB are achieved for 4G & 5G applications. Two symmetric feeding lines orthogonal to each other have been used to obtain the dual-polarization. Also, a high stable gain of 7 ± 1 dBi & HPBW of 80 ± 5° was achieved over the entire operating band at both the ports due to the symmetric structure. The proposed antenna is compared for size and bandwidth with the structures already proposed in the literature and significant enhancement is observed to be used for Base station antennas.

Microstrip filters Based on Open Stubs and SIR for High Frequency and Ultra-Wideband Applications

This paper includes two new microstrip filter configurations for high frequency and Ultra-Wide Band applications. The first proposed filter is a composition of four parallel open-circuited stubs connected by optimized fractal-structured microstrip line. The filter response is a combination of three passing regions, namely low pass from 0.1 GHz to 3 GHz, band-pass from 4.5 GHz to 9 GHz and high pass from 10.5 GHz to 13 GHz, separated by two rejection regions from 3 GHz to 4.5 GHz and 9 GHz to 10.5 GHz. Deep and sharp rejection regions reaching up to -44.6 dB with 40 % fractional bandwidth (FBW) are observed with a good electrical performance. Furthermore, with a comparative table, the advantages of this proposed BSF in terms of FBW, compactness and insertion loss are compared with recently reported related studies. Secondly a dual-band band pass filter implementing a Stepped-Impedance resonator (SIR) and a modified H-shaped structure is presented. This filter is designed to operate in a low pass region up to 3.58 GHz and a band pass region from 15.38 to 21.65 GHz, with a wide stopband region between 4.46 and 14.07 GHz. The simulated and measured results are in good agreement. Compared to its peers, the compact size and low price allow for a wide application of these filter configurations, while passing frequencies allow operation in the unlicensed frequency spectrum, which is popular for high-speed communication. Keywords: Microstrip Filter, Band Pass, Band Stop, Open Stubs, SIR.

Design of Minkowski Array Microstrip Fractal Antenna at 3.5 GHz Frequency for 5G Communication System

Technological developments in the field of telecommunications are experiencing rapid progress, especially the presence of 5G technology as a fifth generation cellular communication system that has many advantages at the World Radiocommunication Conference (WRC) in 2015, 5G candidate frequency bands below 6 GHz have been widely discussed, and the range the following frequencies have been suggested: 470–694, 1427–1518, 3300–3800, and 4500–4990 MHz. One of recommendation of resonant frequency is 3.5 GHz, as it is acceptable in most countries. Therefore, a reliable communication network is needed, especially in the 3.5 GHz frequency band for fifth generation applications. Antena is one of the important communication components in radio communication system. Mikrostrip Antena is a type of Antena that is currently growing because it has the advantage of having a light weight and low profile. This paper proposed development of mikrostrip Antena using the fractal method, increase the gain using the Array method, and achieve the target return loss ≤ -10 dB, VSWR ≤ 2, and gain ≥ 5 dB at frequency of 3.5 GHz for 5G communication sytsem. Proposed Antena is designed using a duroid R5880 substrate with a dielectric constant value of 2.2, a dielectric loss (tan loss) of 0.0009 and a substrate thickness (h) of 1.57 mm. This study resulted in a reduction in Antena dimensions until 53.76% with return loss of -42.48 dB, VSWR 1.02, and a gain of 8.46 dB. The results obtained in this design meet the specifications of the predetermined targets.

Demonstrating Antenna Miniaturisation for Radiolocation Applications using Double Elliptical Patches

Double Elliptical Micro-strip Patch Antenna (DEMPA) is developed out of Double Elliptical Patch (DEP) which is a recently proposed shape of patch. The use of DEP results in higher flexibility in design of patch antenna and thus promotes antenna miniaturisation. The present work is an attempt to demonstrate the miniaturisation of radiolocation antenna through the concept of Design Flexibility (DF). In this paper, optimised neural network model for synthesis of DEMPA has been developed for radiolocation applications for which the earmarked frequency band is 8.50 GHz – 10.50 GHz. With the help of synthesis model, for an arbitrary operational frequency of 9.85 GHz, radiolocation antennas with effective patch area ranging from 142 mm2 to 66 mm2 were designed by using DEPs. In this case, the percentage reduction in effective patch area was found to be 53.52%. It shows that double elliptical patches can be employed to develop miniaturised radiolocation antennas. One prototype antenna was fabricated and tested to demonstrate the efficacy of the methodology adopted. The fabricated antenna had resonance at 10.15 GHz with a reflection coefficient of -20.73dB and bandwidth of 3.106 GHz (from 7.458 GHz to 10.564 GHz). Its Fractional Bandwidth was 34.469%. Positive and reasonably good gain was maintained over the entire working band. At resonance, the peak gain was 4.22 dB.The measured characteristics of antenna were in close agreement with the simulated results. The methodology presented in this paper can also be applied to frequency bands for other wireless applications.

Measurement and comparative analysis of channel parameters of different antenna forms in 5G millimeter wave frequency band

Based on the 5G millimeter wave application frequency band, we carry out channel measurement and channel parameter comparative analysis of omnidirectional antenna, horn antenna and array antenna. The space-alternating generalized expectation-maximization (SAGE) algorithm is used to extract multipath channel parameters, including multipath delay, angle of arrival, multipath strength, etc., and the cluster parameters for multipath components are extracted based on the multipath component distance (MCD) algorithm. The comparison and analysis of the channel parameter differences obtained by different antenna types at the same measurement point show that the channel measurement results of different antennas in the same scenario are quite different. The path loss of the omnidirectional antenna is the smallest, and the root mean square(RMS) delay extension and RMS angle extension of the array antenna are the smallest, and the horn antenna can get more clusters. This article provides comparative analysis data of channel parameter results of different antenna forms for 5G millimeter wave band channel modeling.

A Novel Approach for Low Mutual Coupling and Ultra-Compact Two Port Mimo Antenna Development for UWB Wireless Applications

In this paper, a novel MIMO antenna operating in the UWB frequency band is presented. The proposed new antenna shape is derived from the conventional circular ring patch antenna having a partial ground plane. An array of three Quad-G Shaped Metamaterial structure was used between the antenna elements of the two port MIMO antenna to expand the bandwidth in lower frequency band of UWB application (below 5.567GHz) and reduces the mutual coupling in such expanded band. The proposed MIMO antenna operates over a bandwidth of 8GHz from 4GHz to 12GHz. Over the entire bandwidth, the mutual coupling between antenna element is less than -19.0dB with an inter-element separation of mm. The overall optimized dimensions of the proposed antenna is for a free-space wavelength, λ, calculated at 4GHz. The radiation pattern of the proposed MIMO antenna was analyzed using Combined Results Technique (CRT) integrated in CST microwave studio. The obtained peak radiation efficiency and gain is 83.0% and 5.57 dB respectively. The MIMO Performance metrics such as envelope correlation coefficient (ECC), diversity gain (DG), channel capacity loss (CCL), Mean Effective Gain (MEG), and multiplexing efficiency are evaluated and compared to the standard values. The proposed antenna was compared to other antennas in literature. It has found that the key benefit of the present method was observed in achieving the highly miniaturized overall antenna dimension having good MIMO system performance metrics and better radiation characteristic. The proposed antenna was fabricated and measure. The measured and simulated values are found to be in good agreement.

A compact triband miniaturized MIMO antenna for WLAN applications

This paper proposes a four-port, four-element multi-band Multiple-Input Multiple-Output (MIMO) antenna array that resonates at 2.4 GHz, 2.9 GHz, and/or 5.8 GHz frequency bands for WLAN applications. A Complementary Split Ring Resonator (CSRR) was designed on the ground plane of the FR4 substrate with a rectangular patch antenna on the top plane for antenna size miniaturization, bandwidth improvement, compactness, and isolation enhancement. At first, the presence of the CSRR on the conventional antenna creates additional frequency bands and reduces the frequency of the conventional patch antenna from 24.2 GHz to 5.8 GHz. Even though the CSRR as radiating elements are closer to each other at λ/4 in the MIMO design, minimum isolation is achieved by limiting the unnecessary surface current flow that exists between the elements of the antenna. Consequently, an orthogonal method of the antenna element is adopted for the four-port MIMO antenna system with high port-to-port measured isolation of less than −19 dB, −18 dB, and –22 dB for 2.4 GHz, 2.9 GHz, and 5.8 GHz frequency bands respectively. Antenna size reduction of 96.87%, 95.41%, and 81.10% and gain of 3.94 dBi, 3.80 dBi, and 4.08 dBi were achieved for the miniaturized multi-band antenna operating at 2.4 GHz, 2.9 GHz, and 5.8 GHz frequency bands, respectively. The results also provided overall good diversity performances with the ECC < 0.01, DG > 9.98, MEG < 3 dB, and TARC in all of the proposed multi-band MIMO antenna systems at respective frequencies. The reflection & transmission coefficients, surface currents, radiation patterns, total efficiency, and diversity parameters are presented and discussed. Moreover, the proposed integration of CSRR with the antenna for MIMO antenna arrays has the advantage of multi-band operation, size reduction, isolation enhancement, good diversity, and high gain performances. With this, it is possible to conclude that the proposed metamaterial multi-band MIMO antenna is the right candidate for WLAN applications.

The Comparative Analysis of Graphene Nano-based and Copper Nano-based Patched Antenna using HFSS

Patch material plays a significant role in controlling the performance and resonating frequency of patch based antennas. In this work, we compared graphene and copper nano-based patch antennas in terms of return loss, bandwidth, gain, directivity and voltage standing wave ratio (VSWR). The simulation is carried out using high frequency structure simulator HFSS. The substrate material used is Silicon dioxide. The antenna is designed to operate in the THz frequency band of (1-15THz) with the fundamental frequency of 5.5THz. The result shows that, the classical metallic antennas with copper material resonant at lower frequency of 3THz while graphene resonant at the higher frequency of 7THz, this is due to high electrons mobility in graphene than in copper. Graphene based patch antenna achieves maximum return loss of -24.4555dB with the corresponding VSWR of 1.0413. The maximum gain of 7.1943dB is achieved with a bandwidth of 522.3GHz; this shows better antenna performance than copper except the bandwidth. The contemporary copper antenna attains return loss of -14.7028dB with the corresponding VSWR of 3.2336. The gain of 4.6219dB is achieved with a bandwidth of 1188.5GHz. With this result, it can be seen that graphene is a suitable choice and can replace copper patch material for patch antennas for wireless applications in terahertz frequency band.

Design Of Frequency Reconfigurable Microstrip Antenna

Due to the rapid evolution in electronics and wireless communication, the demand for the portable electronic devices operating at different frequency bands for multiple applications has been increased. Frequency reconfigurable antennas play an important role in wireless communication. In our proposed method we designed a micros trip patch antenna using HFSS software in order to increase return losses. The substrate used in this proposed design is FR4 with dielectric constant 4.4 and thickness 1. 6mm. The measured tuning of the designedantenna ranges from 2.5 to 5GHz. The value of VSWR is in the range of 1-2 in this range of frequency. The return losses obtained in our designed antenna is 23Db

Overview of Intelligent Transport System (ITS) and Its Applications

Since last decades world, predominantly urban areas, is experiencing huge voluminous road traffic growth, resulting in heavy congestion, air pollution, accidents, and poor efficiency. Many people every day are the victims of this poor management of tremendous traffic. Since many years, there had been some automation in managing the traffic namely Electronic Toll Collection (ETC), Electronic parking payment, normal traffic information etc. However, there are little efforts for making the system more advanced. Recently, several kinds of research are being launched by many countries to develop Intelligent Transport System (ITS), with the objectives to minimize congestion, ensure better safety, reduce air pollution etc. ITS are planned to establish robust communication between vehicle to vehicle (V2V), vehicle to pedestrian (V2P), vehicle to infrastructure (V2I), and vehicle to network (V2N). Initially, for communication links ITS, deploys Wi-Fi network, but because of limited capacity and huge requirement, some links use 5.8 GHz radio frequency for such purposes. IEEE, International Telecommunications Union (ITU) and other advanced research organisations are studying 700 MHz band and mm frequency bands for advanced ITS. ITS is poised to use Information &amp; Communication Technology (ICT) networks for such purposes. ITU has established Study Groups/study questions for addressing ITS issues. The World Radio Conference (WRC-2019) has made a Recommendation 208 regarding harmonization of frequency bands for ITS applications. This paper presents a comprehensive overview of ITS, its applications and analysis etc. The radio frequency spectrum aspects and role of 5 G in ITS are also described in detail.

A single‐layer high‐gain dipole antenna array with a bidirectional radiation pattern based on parallel‐strip line

A single-layer dipole antenna array with quasi-Yagi configuration has been proposed and demonstrated, which provides a dual radiation pattern with the same sense. This antenna is mainly composed of a substrate-supported parallel strip line (PSL) and several periodic dipole elements. Fed by PSL, dipole elements can be stimulated with a uniform power, forming a linear dipole antenna array. By adjusting the elements separation appropriately, the step phase of array factor can be tuned to achieve the same directivity as the element dipole. When an SubMiniature version A (SMA) coaxial connector is connected at the beginning of PSL, the fundamental mode TEM in the PSL is excited and the radiation electromagnetic wave from the dipole elements is achieved. A taper line between the SMA and PSL can be used to reduce the discontinuity, minimizing the reflection coefficient of the port. According to the theory of classical Yagi antenna, the gain can be further improved by introducing multiple directors, achieving the gain increment of about 3 dBi in the proposed design. Considering 5 GHz frequency band applications (4.85–5.2 GHz), the experimental and simulated results show the proposed antenna array has a working bandwidth ( | S 11 | ≤ − 10 d B ) from 4.85 to 12 GHz.

Infinity Shell Shaped MIMO Antenna Array for mm-Wave 5G Applications

In this paper, a novel single layer Multiple Input–Multiple Output (MIMO) antenna for Fifth-Generation (5G) 28 GHz frequency band applications is proposed and investigated. The proposed MIMO antenna operates in the Ka-band, which is the most desirable frequency band for 5G mm-wave communication. The dielectric material is a Rogers-5880 with a relative permittivity, thickness and loss tangent of 2.2, 0.787 mm and 0.0009, respectively, in the proposed antenna design. The proposed MIMO configuration antenna element consists of triplet circular shaped rings surrounded by an infinity-shaped shell. The simulated gain achieved by the proposed design is 6.1 dBi, while the measured gain is 5.5 dBi. Furthermore, the measured and simulated antenna efficiency is 90% and 92%, respectively. One of the MIMO performance metrics—i.e., the Envelope Correlation Coefficient (ECC)—is also analyzed and found to be less than 0.16 for the entire operating bandwidth. The proposed MIMO design operates efficiently with a low ECC, better efficiency and a satisfactory gain, showing that the proposed design is a potential candidate for mm-wave communication.