Antipodal Linearly Tapered Slot Antenna Research Articles

A Millimeter-Wave Antipodal Linearly Tapered Slot Antenna Array for 5G Wireless Communication

This paper presents an antipodal linearly tapered slot antenna (ALTSA) array with the newly emerging substrate-integrated coaxial line (SICL) technology. Each element of the proposed array consists of two vertically stacked antipodal tapered slot antennas (TSA) with the inner conductor of a SICL as the shared fin. The vertical symmetry of this radiating element structure significantly suppresses the cross-polarization level. By employing a SICL-based power splitter with differential outputs, a two-element array with horizontal symmetry is formed. With the inner conductors of two parallel SICLs combined as the flaring metal shared by adjacent tapered slots, the main beam squint is effectively suppressed. Experimental results show an actual −10-dB impedance bandwidth (BW) of 24.5∼34.4 GHz, and the realized gain range measured is 16.1∼18.7 dBi. The cross-polarization levels are −39.4 dB/−40.7 dB at 30 GHz for the E-/H-planes. The measured results agree well with the simulated data which demonstrates the feasibility of the proposed SICL-based ALTSA scheme in the potential 5 G·millimeter-wave (mmWave) applications.

Antipodal Linearly Tapered Slot Antenna with Quasi-Hemispherical Pattern Using Subwavelength Elements

Antennas with quasi-hemispherical radiation patterns are preferred in many wide−area wireless communication systems which require the signals to uniformly cover a wide two−dimensional region. In this work, a simple but effective beamwidth broadening technique based on an antipodal linearly tapered slot antenna (ALTSA) is first proposed and then experimentally verified. Compared with most of the reported designs, the proposed antenna can significantly widen beamwidth and achieve a quasi-hemispherical radiation pattern without increasing the overall size and structural complexity. Only two rows of subwavelength metallic elements (eight elements in total) are simply and skillfully printed at specified positions on the dielectric substrate (relative permittivity εr = 2.94 and thickness h = 1.5 mm) of a general ALTSA whose peak gain is 11.7 dBi, approximately 200% half-power beamwidth (HPBW) enlargement can be obtained in all cut-planes containing the end-fire direction at the central frequency of 15 GHz, and the HPBW extensions in different cut-planes have good consistency. Thus, a quasi-hemispherical beam pattern can be acquired. Thanks to the simplicity of this method, the antenna size and structural complexity do not increase, resulting in the characteristics of easy fabrication and integration, being lightweight, and high reliability. This proposed method provides a good choice for wide−beam antenna design and will have a positive effect on the potential applications of wide-area wireless communication systems.

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.

Diverse SRRs Loaded Millimeter-Wav SIW Antipodal Linearly Tapered Slot Filtenna With Improved Stopband

An antipodal linearly tapered slot filtenna (ALTSFA) with diverse split-ring resonators (SRRs) is proposed. The ALTSFA is actually an antipodal linearly tapered slot antenna (ALTSA) fed by a substrate integrated waveguide (SIW) whose cutoff characteristic is utilized to obtain a lower band suppression. A broad-coupled complementary SRR (BC-CSRR) and 11 SRRs on the ALTSA are used to achieve an upperband suppression. Hence, filtering function with wide stopbands is achieved without enlarging its size and deteriorating the radiation performance. A prototype of the proposed ALTSFA was fabricated and measured, and a bandwidth ranging from 23.5 to 27.5 GHz, a maximum gain of 10 dBi, and a maximum out-of-band suppression of 20.55 dB are observed, validating its good performance. The proposed ALTSFA can be a promising candidate for compact fifth-generation mobile communications and beyond (5G/B5G) millimeter-wave communication system.

Combined Planar Endfire Circularly Polarized Antenna Using Unidirectional Dielectric Radiator and Thin Substrate Integrated Waveguide Feeder

This article proposes and presents a fully planar endfire circularly polarized (CP) antenna with mingled three-layer substrates. It consists of a unidirectional dielectric radiator (UDR) and an antipodal linearly tapered slot antenna (ALTSA) surrounded by a UDR. The ALTSA is fed by a substrate integrated waveguide (SIW) on a thin substrate of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.05\lambda _{0}$ </tex-math></inline-formula> , which can easily be integrated with RF subsystems. The UDR is fed by the ALTSA, which enables the UDR to enhance the original vertically polarized radiation rather than the horizontally polarized radiation from the ALTSA. Due to the polarization selectivity enhancement, an endfire CP antenna with a very thin substrate is created. An experimental prototype of the proposed antenna has been studied, designed, and measured. The measured impedance bandwidth of −10 dB covers a broadband of 29.7 GHz from 26.1 to 55.8 GHz, and the 3 dB AR bandwidth is 19.7 GHz ranging from 25.3 to 45 GHz. The measured gain is over 9 dBic from 27.8 GHz to over 32 GHz. A good performance with a small size of only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.57\lambda _{0} \times 0.78\lambda _{0} \times 0.33\lambda _{0}$ </tex-math></inline-formula> , including the CPW-SIW transition, makes it an attractive option in the development of high gain planar endfire CP antennas and arrays for 5G and B5G applications.

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.

W-Band Endfire 2-D Phased-Array Transmitter Based on ×9 CMOS Active Multiplier Chips

In this article, we propose a scalable approach for a $W$ -band 2-D beam steering transmitter based on CMOS active frequency multiplier chips. Stacking of PCBs containing linear-phased arrays with endfire antennas is used with $X$ -band power splitting and phase control. The antenna design is discussed, explaining the choice of the SIW fed antipodal linearly tapered slot antenna (ALTSA). The concept is demonstrated in the 90–100 GHz bandwidth with $1\times 2$ , $1\times 4$ , and $2\times 2$ arrays, achieving up to 29.4 dBm EIRP and ±10° of beam steering. Measurement results show excellent agreement with simulations, demonstrating the possibility of scalable 2-D phased arrays in $W$ -band with low-cost small silicon area consumption.

Specific Absorption Rate Distributions of a Tapered Slot Antenna at 60 GHz in Personal Wireless Devices [Wireless Corner

In the near future, new-generation wireless networks are expected to provide new paradigms over the existing networks with a wide variety of wireless broad-band applications. With this perspective, progress in computational electromagnetics (EM) and advances in utilizing millimeter-wave (mm-wave) frequency bands provide candidates for high-resolution, highspeed broad-band wireless systems/applications. With the advances in wireless technologies and from a publicsafety viewpoint, the biological and health effects induced by mm-waves should be carefully considered before their deployment in the near future. The objective of this study is to analyze the specific absorption rate (SAR) of an antipodal linear tapered slot antenna (ALTSA) operating at 60 GHz utilizing substrate integrated waveguide (SIW) technology for personal wireless devices (PWDs). For a better understanding of the interactions between the human body and antennas for wireless devices like laptops and headphones, SAR at the head and anterior thigh positions and temperature rises have been characterized numerically and computationally using EM simulation tools with phantom models.

Substrate Integrated Waveguide Based High Gain Planar Antipodal Linear Tapered Slot Antenna with Dielectric Loading for 60 GHz Communications

The 60 GHz band has the potential to provide high speed wireless communication. Substrate integrated waveguide (SIW) fed millimeter wave high gain antipodal linear tapered slot antenna (ALTSA) is presented in this paper. To obtain high gain the dielectric loading in addition to the corrugation structure is applied to the ALTSA. The use of SIW technology allows a highly efficient, compact and low cost planar design. The antenna is designed and simulated in an electromagnetic field simulation tool. A single element ALTSA is designed first. Then SIW power divider is used for designing 1 × 4 ALTSA array. To validate the proposed design, prototypes have been fabricated and measured. The simulated results agree well with the measured values which validates the proposed design. The measured return loss of single-element ALTSA and 1 × 4 ALTSA array is better than 12 dB over the entire 60 GHz band (57–64 GHz). The measured gain for single-element ALTSA and 1 × 4 ALTSA array is 18.7 ± 0.4 dBi and 22.9 ± 0.6 dBi respectively over the 60 GHz band.

SIW Based Antipodal Linear Tapered Slot Antenna for Inter-Satellite Communication Links at 60 GHz

Future space exploration demands inter-satellite links (ISL) that allow high speed communication between two or more satellites. This paper is concerned with the antenna system capable of establishing and maintaining ISL at 60 GHz. A high gain corrugated and hat shaped dielectric loaded antipodal linear tapered slot antenna (ALTSA) based on substrate integrated waveguide technology for inter-satellite communications at 60 GHz is proposed in this paper. A gain of 16.2 dBi achieved with a single element corrugated ALTSA and the 1 × 2 corrugated ALTSA array has a gain of 18.5 dBi with return loss below −10 dB at 60 GHz band. Similarly, the hat shaped dielectric loaded ALTSA has gain of 17.29 dB with single element and 19.22 dB was achieved with two elements ALTSA. Both have good radiation efficiency of above 92%. Electromagnetic field simulation tools have been utilized for the design and simulation of the proposed antennas.

Analysis and Design of a Novel Circularly Polarized Antipodal Linearly Tapered Slot Antenna

This paper presents and characterizes a novel antipodal linearly tapered slot antenna for generating the circularly polarized (CP) field. By introducing two symmetrical slots on the top and bottom layers of a rectangular WR-15 waveguide, we could obtain circular polarization with an axial ratio bandwidth of 34.1%. The waveguide was used to feed the proposed antenna with very wideband impedance matching. The antenna can achieve impedance bandwidth of 40% for S(1,1) <−15 dB from 50 to 75 GHz. The simulation and measurement results show that the antenna can produce very good radiation patterns, with stable gain of 9.8 dBi ± 1.24 dBi, low back radiation, and narrow beamwidth over the operating frequency range. The working principle of this CP antenna is explained, using theoretical equations and explicit current distributions. The proposed antenna is easy to manufacture and is a compact candidate for high performance CP millimeter-wave antenna.

Millimeter-Wave Air-Filled SIW Antipodal Linearly Tapered Slot Antenna

The emerging millimeter-wave wireless technologies spur the development of low-cost and high-performance devices, circuits, and systems. It is in this context that an air-filled substrate integrated waveguide (AFSIW) antipodal linearly tapered slot antenna (ALTSA) made of a multilayer printed circuit board process is proposed in this letter. The proposed three-layered AFSIW structure provides very low loss and is of high interest for the design of highly efficient ALTSA. For comparaison, the proposed AFSIW ALTSA and a convientional SIW ALTSA are designed, fabricated, and measured at Ka -band (26–40 GHz). For identical dimensions, at 35.5 GHz, the proposed antenna exhibits a 17° narrower measured xy -plane half-power beamwidth and a simulated radiation efficiency improved by 2.9%. The narrower beamwidth and efficiency improvement results in a simulated directivity and measured gain improved by 3.9 and 4 dB, respectively, at the same frequency. This antenna is of interest for the design of efficient array based on AFSIW feeding network.

Antipodal Linear Tapered Slot Antenna Based Radio Link Characterization in Narrow Hallway Environment at 60 GHz

The performance of wireless communication systems is predominantly dependent on propagation environment and respective radiating antennas. Due to the shorter wavelength at millimeter wave (MmW) frequencies, the propagation loss through the objects in indoor environments is typically very high. To improve the channel capacity and to reduce inter-user interference, a high gain directional antenna is desired at MmW frequencies. Traditional antennas used in MmW devices are not suitable for low-cost commercial devices due to their heavy and bulky configurations. This paper focuses on design and development of a very compact (44.61 × 9.93 × 0.381 mm) high gain antipodal linear tapered slot antenna (ALTSA) utilizing substrate integrated waveguide (SIW) technology at 60 GHz. Received signal strength (RSS), path loss, and capacity are studied for MmW indoor applications utilizing ALTSA with radio frequency (RF) measurement equipment in narrow hallway environment.

60 GHz radio link characteristic studies in hallway environment using antipodal linear tapered slot antenna

Millimetre-wave (MmW) frequencies offer large bandwidth with which gigabit data rates can be easily achieved with simple radio architectures. At MmW frequencies, the short wavelength enables integration of the antenna on the same chip as the microwave monolithic integrated circuits. This research work emphasises on the design and development of antipodal linear tapered slot antenna (ALTSA) using substrate integrated waveguide (SIW) technique and its radio link characteristics at 60 GHz for wireless local area network and wireless personal area network applications. SIW feeding technique is used to eliminate the unwanted radiations from feed. The proposed antenna is designed and simulated using three-dimensional (3D) electromagnetic tools. Radio propagation is profoundly site specific and depends on frequency of operation, interference from surroundings and other dynamic factors. To predict signal strength, delay and achievable data rates, it is important to characterise the radio channel. The radio link study is carried out using ALTSA with radio frequency measurement equipment to measure and characterise propagation channels in narrow hallway environment at 60 GHz.

A Planar Feeding Technology Using Phase-and-Amplitude-Corrected SIW Horn and Its Application

As traditional horn antennas that could be used as feeds for reflector antenna systems, substrate integrate waveguide (SIW) horns could be used as feeds for planar antennas and arrays. In this letter, a phase-and-amplitude-corrected SIW horn by metal-via arrays is presented as a planar feeding structure. The compact SIW horn is applied to feed two $1\times 8$ antipodal linearly tapered slot antenna (ALTSA) arrays, forming sum and difference beams at X-band. The measured gain of the sum beam is 12.84 dBi, the half-power beamwidth is $18.6^\circ $ , the FTBR is 15.07 dB, and the sidelobe level is $-$ 20.79 dB at 10.1 GHz. The null depth of the difference beam is $-$ 44.24 dB. Good agreement between the simulation and the measured results is obtained.

PERFORMANCE INVESTIGATIONS WITH ANTIPODAL LINEAR TAPERED SLOT ANTENNA ON 60 GHZ RADIO LINK IN A NARROW HALLWAY ENVIRONMENT

The performance of wireless communication systems is predominantly dependent on propagation environment and respective radiating antennas. Due to the shorter wavelength at Millimeter Wave (MmW) frequencies, the propagation loss through surroundings in indoor environments is typically very high. To improve the channel capacity and to reduce inter-user interference, a high gain directional antenna is desired at MmW frequencies. Traditional antennas used in MmW devices are not suitable for low-cost commercial devices due to their heavy, bulky and expensive configurations. This paper focuses on design and development of a very compact (44.61 mm × 9.93 mm × 0.381 mm) high gain Antipodal Linear Tapered Slot Antenna (ALTSA) utilizing Substrate Integrated Waveguide (SIW) technology at 60 GHz. Received signal strength (RSS), path loss (PL) and capacity are studied for MmW based wireless applications utilizing electromagnetic (EM) computations and Radio Frequency (RF) experiments in narrow hallway environment.

Planar High-Gain Dielectric-Loaded Antipodal Linearly Tapered Slot Antenna for $E$- and $W$-Band Gigabyte Point-to-Point Wireless Services

The concept of substrated integrated waveguide (SIW)-fed horn and antipodal linearly tapered slot antenna (ALTSA) are jointly used to design a low-cost, high-gain, and efficient planar dielectric-loaded antenna for ultra-wideband gigabyte wireless services, which are demonstrated over <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> - and <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">W</i> -bands. SIW is used to feed the proposed antenna. To increase the gain of the antenna, a dielectric-loaded slab is used in front of the antenna and works as a dielectric guiding structure. The SIW feed, the proposed antenna, and the loaded dielectric are all integrated in a planar single layer substrate, resulting in low cost and easy fabrication. Low-cost printed circuit board (PCB) process is utilized to fabricate the antenna structure with rectangular and elliptical shaped loaded dielectrics. Measured bandwidth of the antenna covers both <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> - and <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">W</i> -bands (70-110 GHz). Measured gain of the single-element antenna is 14±0.5 dBi, while the measured radiation efficiency of 84.23% is obtained at 80 GHz. Wideband SIW power dividers are used to form a 1 × 4 array structure. Measured gain of the 1 × 4 array antenna is 19±1 dBi, while the measured radiation pattern and gain are almost constant within the wide bandwidth of the antenna.

Broadband CPW Feed for Millimeter-Wave SIW-Based Antipodal Linearly Tapered Slot Antennas

To achieve broadband performances in the millimeter-wave range, antipodal linearly tapered slot antenna (ALTSA) designs with new combined substrate integrated waveguide (SIW) and regular coplanar waveguide (CPW) feeds are presented and studied. This feed structure eliminates the fabrication of air bridges in direct CPW-fed tapered slot antennas (TSAs). Two millimeter-wave design techniques are introduced for the selected 41-61 GHz and 90-120 GHz frequency ranges, demonstrating very good impedance match and nearly constant gain, beamwidth, and cross-polarization levels over bandwidths of 39% and 28%, respectively. The design procedure is validated by comparing simulated results with measurements performed on a 21-31 GHz (38% bandwidth) prototype. Very good agreement between measured and calculated performance characteristics is obtained with only cross-polarization levels slightly higher than predicted. The structural design parameters and dimensions of all three designs are given.

Air-Filled Parallel-Plate Cylindrical Modified Luneberg Lens Antenna for Multiple-Beam Scanning at Millimeter-Wave Frequencies

This paper presents a novel design of cylindrical modified Luneberg lens antenna at millimeter-wave (mm-wave) frequencies in which no dielectric is needed as lens material. The cylindrical modified Luneberg lens consists of two air-filled, almost-parallel plates whose spacing continuously varies with the radius to simulate the general Luneberg's Law. A planar antipodal linearly-tapered slot antenna (ALTSA) is placed between the parallel plates at the focal position of the lens as a feed antenna. A combined ray-optics/diffraction method and CST-MWS are used to analyze and design this lens antenna. Measured results of a fabricated cylindrical modified Luneberg lens with a diameter of 100 mm show good agreement with theoretical predictions. At the design frequency of 30 GHz, the measured 3-dB E- and H-plane beamwidths are 8.6° and 68°, respectively. The first sidelobe level in the E-plane is -20 dB, and the cross-polarization is -28 dB below peak. The measured aperture efficiency is 68% at 30 GHz, and varies between 50% and 71% over the tested frequency band of 29-32 GHz. Due to its rotational symmetry, this lens can be used to launch multiple beams by implementing an arc array of planar ALTSA elements at the periphery of the lens. A 21-element antenna array with a -3-D dB beam crossover and a scan angle of 180° is demonstrated. The measured overall scan coverage is up to ±80° with gain drop less than -3 dB.

Photonic Heterodyne Pixel for Imaging Arrays at Microwave and MM-Wave Frequencies

The use of photonic heterodyne receivers based on semiconductor optical amplifiers to be used in imaging arrays at several GHz frequencies is evaluated. With this objective, a imaging array based on such photonic pixels has been fabricated and characterized. Each of the receiving optoelectronic pixels is composed of an antipodal linear tapered slot antenna (LTSA) that sends the received RF signal directly to the electrical port of a semiconductor opticalamplifier (SOA) acting as the optoelectronic mixer. Both the local oscillator (LO) and the intermediate frequency (IF) signals are directly distributed to/from the array pixels using fiber optics, that allows for remote LO generation and IF processing to recover the image. The results shown in this work demonstrate that the performances of the optoelectronic imaging array are similar to a reference all-electronic array, revealing the possibility of using this photonic architecture in future high-density, scalable, compact imaging arrays in microwave and millimeter wave ranges.