Taper Slot Research Articles

A Compact Sinusoidally Tapered Slot Vivaldi Linear Antenna Array for X and Ku Band Applications

A Compact Sinusoidally Tapered Slot Vivaldi Linear Antenna Array for X and Ku Band Applications

Vivaldi Tapered Slot Antenna for Microwave Imaging in Medical Applications

Microwave imaging has become an active research area in recent years, owing primarily to advancements in detecting the early stages of cancer. The study aimed to create a high-gain compact Vivaldi Tapered Slot antenna (VTSA) for microwave imaging in medical applications and also aims to address several challenges in the development of microwave imaging (MWI) technology for medical applications. These challenges include the ability to detect and identify abnormalities in human tissue and considering safe Specific Absorption Rate (SAR) limits for patients, the approach of balancing of penetration and resolution can be done on the design. The antenna operates at frequencies ranging from 1.7 to 3.1 GHz and is built on a low-cost Flame Retardant-4 (FR-4) substrate with a thickness of 1.6 mm. A compact exponential VTSA is initially presented while designing the proposed antenna for broad impedance bandwidth performances. The simulation used a back-to-back linear array of antennas with or without a phantom, specifically a without phantom (only antennas), a water phantom (cube shape), and an anomaly inside the water phantom. The results revealed a significant shift in the signal graph between the three results, indicating a difference in values between the three simulations. A transient domain solver calculation was used in the simulation. The designed antenna improved a gain of 6.09 dBi and a SAR of 0.326 W/kg by maximizing the edges of the exponential in the tapered section and the feedline slot area. The antenna exhibits differences in scattering parameters on each simulation of anomalies across the required frequency range. The result finds suitability of the experiment and simulation in assessing the microwave imaging capabilities. With the data presented, simulated antennas can be used for microwave imaging. The next study should aim on making a suitable imaging system with dimensions that supported in the antenna range and specifications.

A Compact Broadband Monopole Tapered Slot Antenna With High Field Uniformity for Vehicle EMC Test From 20 to 220 MHz

A compact broadband monopole tapered slot antenna (MTSA) for vehicle electromagnetic compatibility (EMC) tests in the semi-anechoic chambers (SAC) is proposed and investigated. The proposed MTSA takes the metal ground of the SAC as part of an antenna. With the mirroring effect of the ground plate in the SAC, the proposed MTSA acts as a conventional tapered slot antenna (TSA) but with only a half size of the conventional TSA, and also avoids the adverse effect of the ground reflections on the field uniformity effectively. Moreover, the MTSA has a slot on its flaring plate that reduces its weight by 30%. Both the simulated and the measured results show that the proposed MTSA achieves a standing wave ratio (VSWR) below 2:1 from 20 MHz to 220 MHz, and a good uniformity, with radial uniformity better than 3 dB, transverse uniformity better than 4 dB. The simulated gains are from 6 dBi to 13.5 dBi with radiation efficiencies over 90% across almost the entire bandwidth.

Fluid flow and heat transfer characteristics of three-dimensional slot film cooling in an annular combustor

Film cooling methodologies in air-breathing gas turbines have been evolving for many decades. In the present work, a combined experimental and numerical parametric study is conducted to investigate the three-dimensional slot film cooling of an annular combustor. The experimental investigation is conducted to understand the fluid flow and heat transfer phenomenon of the film cooling and to validate the numerical study under laboratory conditions (low temperature and pressure). Transient infrared thermography is used to estimate both adiabatic film-cooling effectiveness (ηad) and heat transfer coefficient (h) simultaneously using a semi-infinite approximation method. The blowing ratios considered in the study are in the range of 0.5 to 5. The experimental results showed that film-cooling effectiveness (ηad) enhanced with an increase in the blowing ratio from 0.5 to 2 and deteriorated beyond BR = 2 due to the adverse effects of turbulence. A parametric study is conducted numerically to understand the effect of flow and geometrical parameters under actual engine conditions (high temperature and pressure). The parameters considered are slot Reynolds number (Res), slot jet diameter (d), slot jet pitch (p), lip taper angle (α), lip length (L), and slot jet injection angle (β). For the considered parameters, numerical results showed that the slot jet diameter (d) = 2 mm, dimensionless slot jet pitch (p/d) = 2, slot jet injection angle (β)=20o and dimensionless lip length (L/d) = 5.9 outperformed the other configurations due to the low turbulence and entrainment. Finally, an Artificial Neural Network-based mathematical model is developed that correlates the ηlat as a function of flow and geometrical parameters.

Ultrawideband Shared-Aperture Crossed Tapered Slot Antenna for 5G Applications

A shared aperture scheme based on a tapered slot configuration is proposed in this letter. The main structure of the proposed antenna is an ultrawideband (UWB) crossed tapered slot with ground. In order to improve the practicality, four 1 × 4 dipole arrays containing feeding networks in the millimeter-wave (mm-wave) band are embedded in the four arms of the crossed tapered slot antenna. Four metal reflectors (or flares) are introduced to increase the gain of the dipole array. Owing to the ultrawideband characteristics of the tapered slot antenna, the proposed slot antenna can cover most sub-6 GHz communication frequency bands (such as LTE bands, N77–N79 bands, etc.). The proposed antenna has a compact volume of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$0.5 \lambda \times 0.5 \lambda \times 0.38 \lambda$</tex-math></inline-formula> , where λ is the free-space wavelength at 1.5 GHz. A prototype is designed, fabricated and tested. The measured results show that a −10 dB impedance bandwidth of 107% (1.5–5 GHz) and 15.8% (25–29.3 GHz) is realized in the sub-6 GHz band and mm-wave band, respectively. The isolation between all ports is higher than 30 dB. The gain variation of the antenna in the low-frequency range is 3.8–7.8 dBi. The peak gain of a single dipole array is approximately 14 dBi. The proposed antenna has the characteristics of shared aperture, low cost, and UWB, which is suitable for 5G microbase station applications.

Broadband Printed Tapered Slot Antenna Fed by CPW Fulfilled with Planar Artificial Magnetic Conductor for X-Band Operation

A low-profile printed slot antenna (PSA) backed by broadband planar artificial magnetic conductor (AMC) is introduced in this study. Firstly, a suggested PSA with the radiating tapered slots excited by coplanar-waveguide (CPW) is used to expand the bandwidth in the measured range of 9-11 GHz (S11≤ -10 dB). Then, the suggested planar AMC surface as the ground plane of the antenna is inserted into the PSA to gain improved radiation efficiency. The realized result from the PSA with the 9×9 planar AMC array exhibits -10 dB measured impedance bandwidth from 6.63 to 13.73 GHz (70%). The suggested PSA with AMC compared to the PSA without AMC exhibits a size reduction of 60%, enhanced bandwidth of 50%, and excellent impedance matching with a minimum value of almost -40 dB. The novel AMC unit cell is realized to operate at 10.14 GHz with an AMC bandwidth of 8-12.35 GHz (43.1%) for X-band operation. Besides, by loading a periodic AMC unit cells into PSA, a high gain of more than 11 dBi with uni-directional radiation patterns is achieved.

Compact 5G Vivaldi Tapered Slot Filtering Antenna with Enhanced Bandwidth

Compact fifth-generation (5G) low-frequency band filtering antennas (filtennas) with stable directive radiation patterns, improved bandwidth (BW), and gain are designed, fabricated, and tested in this research. The proposed filtennas are achieved by combining the predesigned compact 5G (5.975 – 7.125 GHz) third-order uniform and non-uniform transmission line hairpin bandpass filters (UTL and NTL HPBFs) with the compact ultrawide band Vivaldi tapered slot antenna (UWB VTSA) in one module. The objective of this integration is to enhance the performance of 5.975 – 7.125 GHz filtennas which will be suitable for modern mobile communication applications by exploiting the benefits of UWB VTSA. Based on NTL HPBF, more space is provided to add the direct current (DC) biassing circuits in cognitive radio networks (CRNs) for frequency reconfigurable applications. To overcome the mismatch between HPBFs and VTSA, detailed parametric studies are presented. Computer simulation technology (CST) software is used for the simulation in this study. Good measured S11 appeared to be < −13 and < −10.54 dB at 5.48 – 7.73 and 5.9 – 7.98 GHz with peak realized gains of 6.37 and 6.27 dBi, for VTSA with UTL and NTL HPBFs, respectively which outperforms the predesigned filters. Validation is carried out by comparing the measured and simulated results.

Miniaturized Vivaldi Tapered Slot Antenna (VTSA) with Microstrip to SIW Feed Structure for X Band Application

Vivaldi tapered slot antenna (VTSA) families are low-cost, lightweight, and have a simple design structure with good electrical performance and consistent impedance over a wide frequency range. It can be fabricated on a fragile substrate to be used for various applications like an aircraft wing or in wearable networks. One biggest issue with this antenna is impedance matching. In this design, an antipodal Tapered slot antenna is used. The proposed antenna’s feed structure used a SIW (Substrate Integrated Waveguide) to microstrip transition. It allows us to design the characteristics of an antenna on a common substrate while maintaining a high-quality factor. The structure is simulated in CSTMWS (CST Microwave Studio) and the equivalent circuit of the transition part is also evaluated using ADS software tools. The operating frequency range of the structure is between 8 and 12 GHz (X band). This band has potential uses in radar, imaging, medical, space communication, and military applications. The whole structure is fabricated on the RO4003c substrate and measurements are taken with a VNA. The simulated and measured results are found to be very close to each other. The designed structure has a 40% percentage bandwidth and the overall dimension is 33 × 14 mm2.

Novel Compact UWB Vivaldi Nonuniform Slot Antenna With Enhanced Bandwidth

A new theory called Vivaldi nonuniform slot profile antenna (VNSPA) is developed based on the nonuniform transmission lines (NTLs) theory and applied to reduce the size of the predesigned compact ultrawide band (UWB) Vivaldi-tapered slot antenna (VTSA) without affecting its performance in terms of matching and bandwidth. Using this theory, 33% of the taper slot length is reduced, resulting in a novel compact UWB Vivaldi nonuniform slot antenna (VNSA). Furthermore, compactness is achieved by performing parametric studies on VNSA with a final 51.94% size reduction. MATLAB optimization codes, CST simulation, and prototype manufacturing and measurement are used to validate the new theory. The proposed antenna provides a measured S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> < −10.89 dB through 2.9–13.55 GHz with 2.91% and 5.8% bandwidth and maximum realized gain enhancement, respectively, as compared with VTSA’s results. The effectiveness of VNSPA theory is proven by comparing the simulated and measured findings of VNSA and VTSA.

Endfire Circularly-Polarized Antipodal Linearly Tapered Slot Antenna Fed by Slotted Width-Tapered SIW

A low-profile single-layer endfire circularly-polarized (CP) antipodal linearly tapered slot antenna (ALTSA) is proposed and investigated through simulations and experiments. This antenna is a composite structure consisting of a novel width-tapered slotted substrate-integrated waveguide (SIW) and an ALTSA fed by the SIW. The former also serves as a radiator to produce vertically polarized radiation, which is crucial to achieve a fully planar endfire CP antenna when a thin substrate is deployed. Compared to the previous ALTSA fed by the SIW, this proposed antenna utilizes slots on the spare broad walls of the SIW to form an extra slotted width-tapered SIW radiator, which presents an extension of the conventional width-uniform slotted SIW. Moreover, there are no space harmonics in the slotted width-tapered SIW; it is a slow wave that produces the vertically polarized radiation. The proposed antenna is demonstrated at 28 GHz, which is one of the millimeter-wave bands specified for 5G. An experimental prototype of the antenna has an impedance bandwidth of about 9 GHz from 23.8 to 32.8 GHz and an axial ratio bandwidth of about 1.4 GHz from 27.35 to 28.75 GHz, which coincide well with simulated results.

Compact UWB Vivaldi Tapered Slot Antenna

In this paper compact Ultra Wideband (UWB) Vivaldi Tapered Slot Antenna (VTSA) is designed simply by changing its Microstrip to Slot line (M/S) transition. To explain the effect of transition’s shapes on the size and the performance of the UWB VTSA, four models (A–D) with detailed parametric studies are analyzed, designed, and fabricated. As compared to Model A, in Model D the size (42.9 mm × 29.28 mm = 1256.112 mm2) is reduced by 19.25%, and the bandwidth (10.34 GHz) is enhanced by 24.56%, in addition, it provides 6.51 dBi maximum realized gain, and stable end-fire radiation pattern. The validity of the proposed antennas is proven by hardware measurement results.

Multilayer Slab AFSIW Antipodal Linearly Tapered Slot Antenna With Cross-Polarization Reduction

This letter introduces a simple technique to reduce cross polarization in multilayer antipodal linearly tapered slot antenna taking advantage of the slab air-filled substrate integrated waveguide (SAFSIW) topology. The operation mechanism is presented together with simulations and experimental validations. The measured results show a reflection coefficient lower than –17 dB over the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</i> -band. A measured gain of 13 ± 1.35 dBi is observed in the overall <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</i> -band. The proposed broadband structure achieves a measured cross-polarization isolation of better than 16.07 dB at endfire direction over the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</i> -band, which is a significant improvement compared to its multilayer AFSIW implementation counterpart.

A coplanar waveguide tapered slot antenna with beam switching capabilities

&lt;p&gt;A wideband tapered slot antenna (TSA) with three radiating elements for beam switching purpose is proposed in this study. The integrated radiating taper slots in assistance with metal strips acting as switches provided the proposed design with the capability of switching its beam into three different directions while maintaining the antenna performance stable. To validate the accuracy of the proposed design, the prototype was fabricated and measurements were conducted in terms of reflection coefficient (S11), radiation pattern and realized gain towards the three different operating modes. By sequentially, activating the switches, the antenna main beam rotated 90º in the XY coordinates. A realized gain ranging from 4.3 to 6.4 dBi and a wide operating bandwidth (|S11| ≤-10dB) from 3.3 GHz to 5 GHz were observed throughout the antenna performance in simulation as well as in experiment. With the covered bands, the proposed antenna can be suitable for Sub -6GHz wireless communications systems. Improvements of Trapezoid Antenna Gain using Artificial Magnetic Conductor and Frequency Selective Surface.&lt;/p&gt;

Gain enhancements of tapered slot Vivaldi antenna for radar imaging applications

in this paper, a gain enhancement of the UWB Tapered slot Vivaldi antenna (TSVA) for radar imaging application is presented. The proposed antenna has 41×48×1 mm3 dimensions. The proposed antenna operates from 2.7 GHz to more than 12 GHz. The antenna is printed on a 1 mm FR4 dielectric substrate thickness with an exponentially tapered slot shape. The suggested Vivaldi antenna is modified by inserting a polygon form dielectric lens and some periodic unequal lengths director elements consist of three metallic strips on the dielectric lens, which produces an improvement in gain significantly along with center frequency band about 2 dB. The radiation pattern of the proposed antenna has a stable variation with respect to frequency.

A 1 × 2 Taper Slot Antenna Array With Flip-Chip Interconnect via Glass-IPD Technology for 60 GHz Radar Sensors

A low cost, broadband and compact antenna in package solution (AiP) is proposed for 60 GHz low-power radar sensor applications. Following a glass integrated passive device (Glass-IPD) manufacturing process, a compact low cost taper slot antenna (TSA) is designed on a substrate with a thickness beyond Yngvesson's range. To realize high gain and front-to-back ratio, the antenna is optimized by introducing a truncated ground. A 1 × 2 antenna array prototype is realized with a dummy transmission line chip in the dimension of 5 × 7.4 mm 2 . Including the flip chip interconnect, the measured results demonstrate a 10 dB impedance bandwidth of 47.2 ~ 67 GHz. The calculated gain is higher than 6.5 dBi in the end-fire direction over the entire 60 GHz band. Based on a physical RLC equivalent circuit, by co-design of the antenna with solder balls, the flip chip interconnect is compensated with a passive network. For the compensation network, its working bandwidth is from 0.1 to 67 GHz, while its insertion loss at 60 GHz is less than 0.2 dB.

SPPs-Shared Dual-Band Antenna With Large Frequency Ratio

The operating frequency of future communication systems will cover both microwave and millimeter-wave (MMW) bands simultaneously. This paper presents a novel design of spoof surface plasmon polaritons (SPPs) structure-shared dual-band antenna with large frequency ratio, which consists of a planar open sleeve monopole antenna operating at S-band and a taper slot antenna (TSA) at K/Ka-band. In this design, the SPPs structure takes important roles in two aspects: it serves as an equivalent-lens to enhance the gain of TSA and a monopole of the planar open sleeve antenna to keep a low profile. To realize high isolation between the two antennas, a substrate integrated waveguide (SIW) and an integrated coaxial line are designed to feed the TSA and the planar open sleeve monopole antenna respectively. The SPPs-shared antenna shows an enhanced endfire gain of 13.09 dBi in the frequency range of 19.32-32.90 GHz and an omnidirectional gain of 1.06-2.92 dBi over the range of 2.23-3.69 GHz, keeping a compact size. The large frequency ratio of 10.8, low profile and the wide operating bands in both lower and upper frequency ranges can meet many wireless communication applications. Reasonable agreement between the measured and simulated results is observed.

Ultra-Wideband Antennas for Wireless Communication Applications

A review paper concerning wide-band and ultra-wideband (UWB) antennas used for wireless communication purposes in terms of the materials as well as a numerical analysis is presented. These antennas which are taken into account are listed as wide-band microstrip antenna, wide-band monopole antenna over a plate, wide-slot UWB antenna, stacked patch UWB antenna, taper slot (TSA) UWB antenna, metamaterial (MTM) structure UWB antennas, elliptical printed monopole UWB antenna, and flexible wearable UWB antenna. The antennas’ performance is compared based on their size and how they can be applicable for portable communication device applications. This review paper furnishes a proper direction to select varieties of figures in terms of impedance bandwidth, gain, directivity, dimensions, time domain characteristics, and materials affecting these antenna’s characteristics.

Range Distance Measurements Using an UWB Tapered Slot 0.43 GHz to 6 GHz Antenna for IoT Application

Abstract This paper presents a compact and innovative design of a UWB radar sensor. The basis of the proposed UWB short pulse generator is a driver, a pulse sharpened and a Monocycle-forming network MFN. The driver converts the step-like waveform in Gaussian pulses, and the pulse sharpened converts slow rise time waveform edge to a faster one. However, the pulse-forming network forms the adequate and required pattern: Gaussian or monocycle. The purpose of this work is to design and fabricate a high-power and low-cost monocycle pulse generator with high accuracy in order to use it on the Internet of Think application especially for applications in The-four-generation-of-industry. To overcome this challenge, a useful technique has been employed; this technique consists of making the discharge path as short as possible, the measurement results give an output waveform of 0.7 volts in amplitude with a minimum ringing around 3:6% in overshoot at 1 MHz. The generator circuit is completely fabricated using micro-strip structure technology characteristics. Good agreements between the measured and theoretical results are achieved which can consider very attractive in many application fields, especially in IoT Application.

A high gain 60 GHz antipodal Fermi‐tapered slot antenna based on robust synthesized dielectric

AbstractA high performance antipodal Fermi taper slot antenna based on unique synthesized dielectric is presented for ultra‐wideband radar applications at 60 GHz band. Specifically, the synthesized dielectric is implemented based on machined holes concentrates only at aperture area to improve its mechanical robustness for lengthy antenna. Further, it is able to suppress back lobe level by 2.5 dB through curving tapered end of the antenna. Concurrently, sine corrugations and dielectric loading are adopted to improve radiation pattern and gain of the antenna for over 20 dB.

Compact Wideband Circularly Polarized Antipodal Curvedly Tapered Slot Antenna

A method to reduce one direction width of the circularly polarized antipodal curvedly tapered slot antenna, while maintaining the wide axial ratio (AR) and impedance bandwidth and endfire radiation, is proposed in this letter. In this method, the ridge structure in the broad wall of the slotted waveguide is used to increase the current path, which makes the antenna achieving the appropriate phase difference of orthogonal electric fields within narrow antenna width. To validate the proposed method, a prototype of the antenna was fabricated and measured. Experimental results show that the proposed antenna can achieve a bandwidth of 27.6% (50–66 GHz) for both AR S 11<–10 dB and an average gain of 8.39 dBi.