Linear Tapered Slot Antenna Research Articles

Design and Parameter Study of a Small Size Tapered Slot Antenna

A small size microstripline-fed linearly tapered slot antenna (LTSA) with the design of tilt grooves is presented in this paper. A parameter discussion of the grooves shows some important features affect the wide-band and wide-beam characteristic of the antenna. By adopting the tilt grooves, impedance bandwidth is increased and improved across a broad frequency band. The low frequency is largely improved compared with the identical LTSA without grooves. Measured results of the half-power beamwidth (HPBW) of the proposed antenna show an excellent characteristic of radiation pattern at the frequency of 7.5 GHz, 9 GHz and 11 GHz, which make it a good candidate for wide-scan phased arrays.

Compact receiver module for a 94 GHz band passive millimetre-wave imager

A compact receiver module for a 94 GHz band passive millimetre-wave (PMMW) imaging system is developed. This receiver module consists of an antipodal linearly tapered slot antenna (LTSA) and microwave monolithic integrated circuit (MMIC) with flip-chip bonding assembly that provides high radio frequency (RF) performance at low cost. A new microstrip-slot transition developed for the LTSA/MMIC interface is also presented and the design procedure for the LTSA is discussed, which obtains almost the same E- and H-plane beam widths. In addition, a low-noise, high-gain MMIC is discussed using inverted microstrip lines that are developed. Finally, it is shown that the PMMW imager can generate a millimetre-wave image.

Multiple-Mode Selection of Walled-LTSA Array Elements for High-Resolution Imaging to Visualize Antipersonnel Plastic Landmines

We propose a resolution improvement technique for a high-density array of walled linearly tapered slot antennas (LTSAs) in ground-penetrating radar imaging. In the system, we use the walled-LTSA array in a near-field measurement configuration and select various pairs of transmitter and receiver antennas out of the array elements. We prepare four selection modes so that we can practically enhance the imaging resolution. We remove the direct-coupling effect and compensate the path-length fluctuation caused by element individuality and element selection. Experiments demonstrate that the technique realizes higher resolution image acquisition to yield a clearer segmentation of antipersonnel plastic landmines in combination with adaptive image processing, based on complex-amplitude texture, even on a wet laterite soil condition.

SIMULATION OF ULTRA WIDEBAND MICROSTRIP ANTENNA USING EPML-TLM

In this paper the simulation of ultra wideband microstrip antenna is considered.Because of the ultra wideband characteristics of this antenna, it is better to use time domain simulation methods. In this work we use three dimensional transmission line matrix method (3D-TLM) and EPML-TLM algorithm for modeling PML boundary condition directly applied to TLM algorithm.Finally simulation results of some kinds of this antenna (e.g., linear tapered slot antenna and modified planar inverted cone antenna) are presented and compared with measurements and some commercial software's output.

Compact linear tapered slot antenna for UWB applications

A novel ultra-wideband (UWB) antenna consisting of a linear tapered slot in the ground plane and a microstrip to slotline transition is investigated. The antenna possesses a wide bandwidth from 2.95–14 GHz for |S11|<−10 dB and shows stable radiation patterns with an average gain of 3 dBi throughout the band. Measured group delay and transmission characteristics indicate that the antenna has good pulse handling capabilities.

Walled LTSA Array for Rapid, High Spatial Resolution, and Phase-Sensitive Imaging to Visualize Plastic Landmines

We propose a walled linearly tapered slot antenna (LTSA) array to visualize plastic landmines. Previously, we reported an adaptive nonlinear visualization system based on a complex-valued self-organizing map (CSOM) that deals with complex amplitude texture in reflection images at multiple frequencies. The system distinguishes landmines from clutter by paying attention to textural features obtained by high spatial resolution and wideband reflection measurement. Because the system employed a mechanical scan of a pair of horn antennas, the measurement required a long time. An array antenna can reduce the time. The antenna element to be used there should therefore be compact and wideband. This paper reports the design and fabrication of a walled LTSA array visualization system. The antenna element has a 14 times 28 mm aperture size, and works at the 8-12 GHz frequency band. Because the structure is a simple combination of glass epoxy substrates and metal plates, we can easily fabricate low-cost and lightweight arrays. Electrical switches realize a high-speed scanning of 12 times 12 = 144 elements in total. We also report the results of a visualization experiment, in which plastic landmines are clearly visualized with the array in combination with the adaptive CSOM processing. Detection of landmines at frequencies of 10 GHz is only likely to be possible for targets buried a few centimeter deep or where the soil attenuation is very low. This might be a severe limitation of applicability of the method, as in field conditions soil attenuations of 10 dB or considerably more are commonly encountered, requiring the radar to operate at frequencies below 2-3 GHz. The best solution may be a multisensor system comprising these complementary high- and low-frequency radars.

Fan-Beam Millimeter-Wave Antenna Design Based on the Cylindrical Luneberg Lens

A new design of two-dimensional cylindrical Luneberg lens is introduced based on TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> mode propagation between parallel plates, with special focus on ease of manufacturing. The parallel plates are partially filled with low cost polymer material (Rexolite epsiv <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> = 2.54) to match Luneberg's law. A planar linear tapered slot antenna (LTSA) is inserted into the air region between the parallel plates at the edge of the Luneberg lens as a feed antenna, with fine positioning to the focal point of the Luneberg lens to optimize the antenna system performance. A combined ray-optics/diffraction method is used to obtain the radiation pattern of the system and results are compared with predictions of a time domain numerical solver. Measurements done on a 10-cm Luneberg lens designed for operation at 30 GHz agree very well with predictions. For this prototype, 3-dB E- and if-plane beamwidths of 6.6deg and 54deg respectively were obtained, and the sidelobe level in the E-plane was -17.7-dB. Although the parallel plate configuration should lead to a narrow band design due to the dispersion characteristics of the TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> mode, the measurement results demonstrate broadband characteristics with radiation efficiencies varying between 43% and 72% over the tested frequency band of 26.5-37 GHz. The designed cylindrical Luneberg lens can be used to launch multiple beams by implementing an arc array of planar LTSA elements at the periphery of the lens, and can be easily extended to higher mm-wave frequencies.

A W-Band Linear Tapered Slot Antenna on Rectangular-Grooved Silicon Substrate

A W-band (75-110 GHz) coplanar-waveguide (CPW)-fed linear tapered slot antenna (LTSA) on rectangular-grooved silicon substrate is presented. Compared to its ungrooved version, the W-band CPW-fed LTSA shows significantly improved endfire radiation patterns in the whole band. Also, the symmetric patterns together with moderately high gain (8-10 dBi), high front-to-back (F/B) ratio (16-28 dB), and low sidelobe level (SLL; -15 to -17 dB for the E-plane and -11 to -18 dB for the if-plane) are achieved. The proposed CPW-fed LTSA is expected to find applications, such as a transceiver antenna in millimeter-wave wireless communication systems, owing to its easy integration with the uniplanar monolithic millimeter-wave integrated circuits

Linear Tapered Cavity-Backed Slot Antenna for Millimeter-Wave LTCC Modules

In this letter, a linear tapered slot antenna (LTSA) which is backed by an air cavity is proposed and fabricated using low temperature cofired ceramic (LTCC) substrate. Traditionally, the high dielectric constant and the thick LTCC substrate seriously degrade the gain and radiation property performance because a large portion of the radiated fields are confined in the LTCC substrate. However, the proposed LTSA with the air cavity backing structure exhibits a high gain (4.9-6.9 dBi) and a good end fire radiation pattern. Also, the proposed antenna has a wide impedance bandwidth (about 30 from 45 to 75 GHz). Through numerical and experimental analyzes, we found that the proposed antenna can be used for a variety of millimeter-wave applications, due to its broadband operating range and its easy integration with 3-D LTCC module.

A K‐band inverted microstripline‐fed linear tapered slot antenna and its 16‐element E‐plane array

AbstractAn inverted microstripline‐fed linear tapered slot antenna element and a design of its 16‐element E‐plane array are presented in this paper. The element is designed using the finite‐difference time‐domain (FDTD) method. The calculated results show that it has a wide‐impedance bandwidth in the K‐band. To investigate the E‐plane array, the return loss at each element input port, the couplings among elements, and the array's radiation patterns are obtained using the FDTD method. Using a unique three‐piece assembled structure, the array is fabricated and tested experimentally. The measured results show that it has a wide bandwidth and antenna efficiency. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 241–246, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20784

A K‐band suspended microstripline‐fed linear tapered slot antenna and its E‐plane arrays

AbstractA suspended microstripline‐fed linear tapered slot antenna element and its E‐plane linear arrays are presented in this paper. The element is studied and designed using the finite‐difference time‐domain (FDTD) method. The simulated results show that the element has a good antenna performance from 17 to 24 GHz. To build the E‐plane arrays, a unique five‐piece assembled structure which guarantees a uniform air‐filled thin substrate in the suspended microstrip line parallel feed‐network, has been developed. Four E‐plane arrays with different numbers of elements (4, 8, 16, and 32) are fabricated and their antenna gains and patterns are examined experimentally. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 451–455, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20168

A linear tapered slot antenna electromagnetically coupled with perturbed coplanar waveguide

AbstractThis paper considers a linear tapered slot antenna element with electromagnetically coupled feed and discusses the matching and the radiation characteristics. In the proposed antenna element, the coplanar line with perturbed feeder, that is, the coplanar waveguide, is considered as a coupled slot line. Each line is short‐circuited to the ground conductor with different length. By electromagnetic coupling on the single‐sided coplanar dielectric substrate, feed to the linear tapered slot antenna element is realized. The following results are obtained. (1) It is possible to control the coupling magnitude and the matching frequency between the antenna element and the feeder. (2) An equivalent circuit is proposed for the matching characteristics, and the circuit parameters are determined. (3) The characteristics obtained by experiment and with an electromagnetic simulator are compared to the characteristics derived from the equivalent circuit. (4) The radiation directivity is of the single‐direction end‐fire type. A gain of 8.1 dBi and a cross polarization of −16 dB in the front direction are realized. On the basis of these results, it is demonstrated that the proposed antenna element is useful as a planar antenna element. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(8): 13–23, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10218

3-D FDTD design simulation and experimental measurement of a Ka-band planar antipodal linearly-tapered slot antenna (ALTSA)

Three-dimensional (3-D) finite-difference time-domain (FDTD) simulation of a planar broadband Ka-band (25-35 GHz) antipodal linearly-tapered slot antenna (ALTSA) and the experimental measurements are presented. The Berenger perfectly matched layer (PML) absorbing boundary condition is used for the FDTD computation. A printed ALTSA has been realized by using the RT/Duroid PCB substrate. Good agreement between simulation and measurement were achieved.

Evaluation of the BICGSTAB(l) algorithm for the finite-element/boundary-integral method

We discuss the application of non-stationary Krylov-subspace-based iterative solvers to linear systems resulting from the application of the finite-element/boundary-integral method. A fairly new conjugate-gradient-based solver, BICGSTAB(l) is further described. The performance of several solvers is tested on a linearly tapered slot antenna (LTSA). Results showing the convergence characteristics and memory requirements are also given.

Electromagnetic modes in conical transmission lines with application to the linearly tapered slot antenna

A transmission line analysis of the bow-tie antenna and the linearly tapered slot antenna (LTSA) is presented. These structures belong to the class of conical transmission lines defined here in terms of conical coordinates. A complete set of solutions of the Helmholtz equation is obtained exhibiting TE and TM modes. Modal fields are expressed by Lame (1837) and Bessel-Schelkunoff functions. TE and TM eigenmode analysis is particularized to the bow-tie structure. Bow-tie antenna and LTSA are shown to be dual conical transmission lines by the image method and Babinet's principle. The modes of LTSA are calculated on the basis of the results obtained for the bow-tie structure. The radiation pattern of the LTSA is computed as the integral of a closed-form expression of the dyadic Green's function weighted by the modal electric field distribution over the slot aperture. The obtained dominant mode radiation patterns are validated by measurements from the literature. The radiation patterns of the first two-order modes are calculated and compared.

Millimeter-wave tapered-slot antennas on synthesized low permittivity substrates

This paper presents 30-GHz linear-tapered slot antennas (LTSA) and 94-GHz constant-width slot antennas (CSWA) on synthesized low dielectric constant substrates (/spl epsiv//sub r/=2.2). The performance of tapered-slot antennas (TSA) is sensitive to the effective thickness of the substrate. We have reduced the effective thickness by selectively machining holes in the dielectric substrate. The machined substrate antenna radiation patterns were significantly improved independent of the machined hole size or lattice as long as the quasi-static effective thickness remained the same, even if the hole/lattice geometry is comparable to a wavelength. The method was applied at 94 GHz on a CSWA with excellent radiation pattern improvement, making it suitable for f/1.6 imaging array applications.

Characterization and optimization of linearly tapered slot antenna pattern

A parametric study of linearly tapered slot antenna (LTSA) in air and a method for optimization of its pattern are presented. A method of moments code is utilized to investigate the behavior of LTSA’s as the length, height and the taper angle varies. It is shown that the antenna pattern can be improved using a top layer of dielectric material with varying permittivity.

Integrated uniplanar transition for linearly tapered slot antenna

This paper presents the design, fabrication, and numerical modeling of two new uniplanar microstrip-to-coplanar strip (CPS) line transitions and a new variant of the linearly tapered slot antenna (LTSA). This new variant with an integrated uniplanar microstrip-to-coplanar strip line feed is called a V-LTSA. The advantages of these transitions in packaging and monolithic microwave integrated circuits (MMIC) integration are listed. The two transitions and the feed are modeled using finite difference time domain (FDTD) method. The overall agreement between the measured and modeled return-loss and insertion-loss characteristics of two back-to-back transitions is good. The resonance frequencies predicted by the FDTD method are within a few percentage points of the measurements. Furthermore, the V-LTSA with the feed is experimentally shown to have a wide return loss (/spl les/-10 dB) bandwidth, good radiation patterns, and low cross-polarization. The gain of the V-LTSA is 9 dB at the design frequency of 10 GHz. A proof-of-concept package to house the feed is experimentally evaluated and shown to have negligible effect on the antenna characteristics. This type of antenna readily integrates with MMIC packages in an array having a brick architecture. The V-LTSA has potential applications in phased arrays. >

Moment method analysis of linearly tapered slot antennas

AbstractAn accurate Method of Moments (MoM) model is developed and implemented for the analysis of the linearly tapered slot antenna (LTSA). The model employs an unequal size reactangular sectioning for conducting parts of the antenna. Piecewise sinusoidal basis functions are used for the expansion of conductor current. The effect of the dielectric is incorporated in the model by using equivalent volume polarization current density and solving the equivalent problem in free space. The feed section of the antenna including the micro‐stripline is handled rigorously in the MoM model by including slotline short‐circuit and microstripline currents among the unknowns. Comparison with measurements is made to demonstrate the validity of the model for both the air case and the dielectric case. Numerical results for the effect of the dielectric permittivity are presented.

Effect of a dielectric overlay on a linearly tapered slot antenna excited by a coplanar waveguide

AbstractA linearly tapered slot antenna (LTSA) with a dielectric overlay was experimentally investigated. The presence of dielectric overlay alters the guide wavelength of the LTSA, and thus the radiation characteristics of the antenna. Results indicate that dielectric overlay could be used to reduce the physical length and to improve the radiation characteristics of the LTSA. © 1993 John Wiley &amp; sons, Inc.