Transverse Slots Research Articles

Design and analysis of multi‐layer SIW coupler to use in phased array antenna feed network

AbstractIn this paper, a directional coupler is designed using the substrate integrated waveguide (SIW) method. The SIW coupler consists of a double‐layer with transverse rectangular slots in the middle of two layers. The proposed coupler contains three ports. The placement of ports is considered based on the generalization of the power divider network. Each layer is printed on 0.508 mm Rogers RT/Duroid 5880 ( and ). The coupling level is basically controlled by the number and size of the slots. This coupling ratio changes from −5 dB to −13 dB. It is complicated to design a single‐layer feed network for a two‐dimensional phased array antenna. The designed SIW coupler can be easily generalized to the feed network for a 2D phased array antenna that consists of a large number of antenna and phase shifter elements. The SIW coupler is simulated using CST software. The results of the analyses, simulations and experiments indicate good performances of the designed coupler.

Development of a compact transverse slot array antenna using corrugation in groove gap waveguide technology

SummaryWe present the proof of concept of a compact slot array antenna with proper side lobe level in groove gap waveguide (GGW) technology. Four transverse slots are etched at the GGW broad wall along with the nulls of standing TE10 wave existing inside the shorted GGW. To decrease the sidelobes and antenna size, corrugations are applied through the wave path inside the GGW. Proper use of corrugations can reduce the wavelength inside the GGW leading to reduction of the distance between adjacent transverse slots, which can help to suppress the grating lobe problem and consequently enhance the radiation efficiency, which is a challenge in transvers slot array antennas. The designed antenna is optimized to achieve maximum gain, lowest grating lobe level, and return loss at 15 GHz using HFSS simulator. The achieved gain is about 13 dBi, and the SLL is better than 15 dB. To confirm the simulation results, the designed antenna was fabricated and tested. Both simulation and measurement results confirm that the grating lobes are well suppressed at the antenna operating frequency.

High gain low profile horn array with circular polarization using a 3D printed anisotropic dielectric composite material at 38 GHz

In this work, the design of a fully 3D-printed dielectric polarizer based on anisotropic engineered material operating at 38 GHz is presented. The anisotropy conditions to obtain circular polarization are achieved by using an array of dielectric strips, manufactured using two different commercially available filaments for 3D-printing. To illuminate the polarizer, a low-profile horn linear array fed by transverse slots is designed and manufactured. The results show good agreement between simulations and measurements, with the designed polarizer covering the whole operation band of the antenna by keeping a similar gain when compared to the structure without the polarizer.

AnEH2‐mode microstrip leaky‐wave antenna with single beam radiation and backward‐to‐forward scanning

In this work, a leaky-wave antenna (LWA) based on the second higher-order-mode (EH2-mode) microstrip line is proposed for achieving the backward-to-forward beam scanning and single main beam radiation. The original microstrip EH2-mode LWA inherently radiates two symmetric beams in the transversal plane. By loading a series of longitudinal slots, the dual-beam radiation of the antenna is converted into single-beam radiation. To achieve the continuous beam scanning, a series of transversal slots are further etched at each periodic cell correspondingly, where the frequency balanced condition could be satisfied for suppressing the open-stop band. Finally, a prototype of the proposed EH2-mode LWA is designed, implemented and fabricated. The measured results agree well with those results obtained from the simulation, validating the proposed method of single-beam radiation and OSB suppression. The designed antenna in the measurement can scan from −15° to +15° with the frequency varying from 4.7 to 5.4 GHz.

Rotor Transverse Slots’ Influence on Negative Sequence Loss and Heat Distribution Prediction of Large Generators Based on Improved Radial Basis Function Process Neural Network

Owing to the advantages of scientific computation and the data feature support provided by artificial intelligence technology, the theoretical exploration and application research of new computing methods for large generators, one of the most expensive energy equipment in a power system, has become a research hotspot toward solving the bearing limit and operation capacity under abnormal working conditions. Because of many factors affecting the distribution of negative sequence loss and temperature rise that have an extremely complex nonlinear relationship, the traditional calculation and prediction methods of negative sequence conditions cannot suitably reflect the time accumulation effect. Therefore, a prediction method of rotor steady-state negative sequence heating based on radial basis function process neural network is proposed in this paper, and a negative sequence working condition prediction model is established. Accordingly, this study focuses on the study of the relationship among negative sequence heating characteristics, negative sequence component proportion, and transverse slot; additionally, their influence degree, variation relationship, and main principles are further explored that provide a theoretical basis for the design and operation of large generators. As observed from the test results, the steady-state negative sequence condition prediction method based on the improved genetic algorithm radial basis function process neural network features high accuracy; it is a feasible prediction method, specifically for negative sequence conditions of large generators.

Experimental investigation of static pressure characteristics in a slotted short pin array

ABSTRACT A common heat exchange method used for most new designs is the use of heat sinks such as short pin fins. This experimental study investigated the static pressure characteristics developed in a short pin fin. Different fin array arrangements, fin longitudinal and transverse spacing ratios and individual slot heights in the fin were investigated. It was found that the row removed arrangement has superior flow efficiency, but to enhance heat transfer the staggered array is a better choice; the greater the fin spacing and slot height in each fin are, the less the pressure loss was experienced in the array.

A Periodic CPW Leaky-Wave Antenna With Enhanced Gain and Broadside Radiation

In this letter, a periodic coplanar waveguide leaky-wave antenna with enhanced gain and continuous backward-to-forward beam scanning is presented. The leaky-wave antenna is made of coplanar waveguide with two symmetric transversal slots on the ground plane. The gain of the antenna is enhanced because of the radiation of the two slots superimposing in the H-plane. The relationship between Bloch impedance and characteristic impedance of the host coplanar waveguide is then investigated. By introducing a pair of matching slots, an improved impedance matching approach is presented to remove the dramatic variation of Bloch impedance at broadside frequency. Hence, the open-stop band (OSB) can be effectively suppressed and broadside radiation is achieved. Finally, a design prototype is implemented and fabricated as an experimental verification. The simulated and measured results show a good agreement. Both the reflection coefficient and radiation patterns verify that the open-stop band of the antenna is eliminated, while the gain is enhanced.

A substrate integrated waveguide based dual‐band leaky‐wave antenna fed by TE 10 and TE 20 modes

A dual-band leaky wave antenna (LWA) based on substrate integrated waveguide (SIW) is presented in this paper. The radiation elements are composed of a set of periodical transverse slots and a long longitudinal slot that can radiate scanning beams at two different bands under TE10-mode and TE20-mode excitation, respectively. The scanning beams in the two bands both cover the forward region, and polarizations are perpendicular. Under TE10 excitation, the proposed antenna radiates scanning beams in the low band (8.2 GHz ~ 9.1 GHz) with gain varying from 10.6 to 15.9 dBi. Under TE20 excitation, the beams of the proposed antenna scan in the high band of 18.8 GHz ~ 22 GHz with gain varying in 11.7 dBi ~ 16 dBi. The measured results of the fabricated prototype confirm the design theory and simulated results.

Design of a Compact Omnidirectional Leaky-Wave Antenna Fed by Higher Order Mode

This article presents a novel leaky-wave antenna (LWA) based on a dielectric-filled rectangular waveguide (RWG) and fed by a higher order mode. The proposed quasi-uniform LWA has a compact configuration that is suitable for microwave applications, featuring the omnidirectional radiation patterns and low cross-polarization. In the frequency band of interest, the higher order mode, i.e., the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> mode, performs as a fast wave in the proposed quasi-uniform LWA, radiating via the transverse slots etched on the walls. The advantage of the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> mode for LWA applications is analyzed and demonstrated. This higher order mode is excited via a mode convertor from an inline coaxial line to the dielectric-filled RWG. For the reduction in sidelobe levels at high frequencies, −25 dB Taylor amplitude distribution is applied to the etched slots. The dielectric-filled LWA with the inline coaxial feeding is fabricated and measured. The measurement is consistent with the simulation, showing frequency-driven beam-scanning capability with low cross-polarization in the elevation plane. The simulated and measured radiation patterns in the azimuth plane illustrate the omnidirectional radiation patterns and thus confirm the radiating performance of the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> mode in the proposed LWA. The advantages of the scanned beams and omnidirectional radiations are promising for radar systems.

УДОСКОНАЛЕННЯ МЕТОДУ РОЗРАХУНКУ ПАРАМЕТРІВ ПОПЕРЕЧНОГО ДРЕНАЖУ МІЛКОГО ЗАКЛАДАННЯ НА АВТОМОБІЛЬНИХ ДОРОГАХ

An important aspect of the road structure strength and stability ensuring is the issue of subgrade favorable water-thermal regime providing during the service life. The article analyzes the results of research by scientists from different countries on the issues of taking into account the humidification regime and the arrangement of the drainage system on highways. One of the main design parameters of shallow transverse drainages is the distance between the drainage slots. The exact definition of this indicator determines the efficiency of water drainage from planar drainage and makes it possible to optimize the cost of drainage structures installation. In the presented work the questions of the existing normative base on climatological indicators definition and principles of shallow drainages calculation are generalized and tasks of researches on improvement and specification of distance between cross drainage apertures calculation method in such drainages are formulated. The authors propose a new solution to the problems. The developed method is based on the basic of non-uniform smooth-motion of a fluid in prismatic channels differential equation and the hypothesis of VI Chernomsky. The authors developed dependences to determine the distance between the transverse drainage slots in shallow drainages. The developed mathematical equations for the main parameters of transverse shallow drainage on characteristic sections of the highway adequately take into account the main factors influencing the process of moisture migration in the drainage layers and allow to solve problems of water-heat regulation of roads in a new aspect. The results of calculations of the distance between the transverse drainage slots, according to the proposed method, for the conditions of the first roadclimatic zone of Ukraine, the maximum total specific excess of water entering the drainage structure for the sand drainage layer with the value of filtration coefficient 4, 5 and 6 m / day are presented. The obtained data are compared with the calculation results according to the traditional method. Appropriate conclusions are made. KEYWORDS: DRAINAGE SYSTEM, DRAINAGE LAYER, DRAINAGE SLOTS, SHALLOW TRANSVERSE DRAINAGE, ROAD, WATERWAY, SUBGRADE.

On the Behavior of Self-Triplexing SIW Cavity Backed Antenna With Non-Linear Replicated Hybrid Slot for C and X-Band Applications

In this paper, a substrate integrated waveguide (SIW) based self-triplexing antenna (STA) with non-linear replicated hybrid slot (NLR-HS) is presented. To the author&#x2019;s best knowledge, the concept of NLR is the first of its kind in the literature used for obtaining self-triplexed operation. Initially, the SIW cavity is loaded by a hexagonal slot merged with two rectangular transverse slots that together produce two distinct resonances around 5.23 and 7.50 GHz. The variation in resonant frequencies of both lower and upper frequency bands can be modelled by applying NLR on the hexagonal slot. To achieve the self-triplexing operation, a coaxial probe-fed parasitic hexagonal patch is placed concentrically inside the hexagonal slot. The third resonance is centered around 10.82 GHz and can be modelled with the help of the gap between the hexagonal slot and parasitic patch.To validate the proposed idea, the design is fabricated and experimentally tested. Moreover, the antenna shows a front-to-back ratio (FTBR) better than 25 dB, average isolation of 43 dB and measured gain (efficiency) values of 7.33 (97.39&#x0025;), 6.66 (95.82&#x0025;), and 6.28 (97.83&#x0025;) dBi at three resonances. Good agreement between the simulated and measured results makes the proposed STA a good candidate for practical applications.

A dual-beam steering one dimensional periodic leaky-wave antenna for large coverage

This paper proposes a dual-beam leaky-wave antenna (LWA) based on substrate integrated waveguide (SIW) technology. The unit cell of the proposed SIW LWA consists pair of transverse and longitudinal slots etched on the top and bottom surface of the SIW. The unit cell characteristics of LAW have been investigated using dispersion analysis. As a result, the open stopband (OSB) problem is suppressed in the broadside direction. As a result, the dual radiating beam of LWA scans the entire space of the elevation plane (XZ plane) without any severe gain degradation at the broadside and endfire. The proposed SIW LWA antenna works in the band of 11.5 to 15.5 GHz with a peak gain of 13 dBi. The measured results are in accord with simulation results.

Planar Broadband Higher-Order Mode Millimeter-Wave Microstrip Patch Antenna Array With Low Sidelobe Level

AbstractIn this letter, a planar broadband higher-order mode millimeter wave (MMW) microstrip patch antenna array with low sidelobe level (SLL) is presented. For the antenna element, antiphase-TM30 mode is excited by unequally etching the radiating patch with two transverse slots. Meanwhile an SIW-based pin-loaded slot coupling feeding structure is introduced to achieve merits of broadband, low cross polarization and low backward radiation. Then a one-eight power divider with in-phase unequally tapered amplitude distribution is adopted to excite an eight-element array with SLL. The GCPW-SIW transition structure is also selected to achieve broadband impedance matching. Finally, both element and array antenna are optimized and fabricated for verification. For the antenna array, the measured -10 dB impedance bandwidth is from 25.1 to 31.3 GHz (22%) with a maximum gain of 14.6 dBi at 29.5 GHz and a 3dB gain bandwidth of 27.9%. And the measured SLL at 26, 28 and 30 GHz are all less than 20 dB. Index TermsMillimeter-wave (MMW), broadband, higher-order mode, low sidelobe level (SLL).

SIW Resonator-Based Duplex Filtenna

In this communication, a low-profile single-layered duplex-filtenna scheme is proposed by using two feeds, and a common substrate integrated waveguide (SIW) cavity. A rectangular slot is carved on the top of the cavity along the narrower side of the SIW, which splits the cavity into two unequal parts. Each part behaves as a half-mode SIW (HMSIW) resonator which radiates with the help of an additional longitudinal slot and open-end of HMSIW when excited with corresponding feed. Also, two vias have been loaded along the broad side of the transverse slot to tune the impedance bandwidth and improve the selectivity in the passbands. The working process of both HMSIW resonators is similar, thus similar type of electrical performance is expected. By properly optimizing the locations of these vias and transverse-slot dimensions, high isolation between input ports is realized. To validate the proposed concept, design has been fabricated and measured. The measured results show good agreement with the simulated counterparts. The measured result shows that the design exhibits impedance bandwidths of around 3.0% (8.63–8.88 GHz) and 4.2% (9.26 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$ - $</tex-math></inline-formula> 9.66 GHz) for lower and upper-frequency pass channel, respectively. The measured average realized gains in the broadside direction are 3.51 and 4.10 dBi, respectively.

Design of a Dual-Linearly Polarized Endfire Antenna

In this article, a dual-linearly polarized endfire antenna is proposed with high gain and stable radiation patterns. A double-sided slot array antenna (DSSAA) and a corrugated rectangular metal strip (CRMS) are employed to realize vertical and horizontal polarization (HP), respectively. Omnidirectional radiation pattern is obtained by etching transverse slots on both sides of the top and bottom metallic plates of a cavity. Based on the double-sided slot antenna, a DSSAA is proposed and fed by an air-substrate parallel strip line (PSL) for stable endfire radiation patterns. Then, the top plate of the DSSAA is reused as a CRMS for HP and compact size. To verify this concept, an all-metal prototype was fabricated and measured. Both the simulation and experimental results show that the DSSAA and the CRMS could offer the highest endfire gains of 12.5 and 12.9 dB, respectively, within a footprint of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.47\lambda _{0} \times 0.72\lambda _{0} \times 0.13\lambda _{0}$ </tex-math></inline-formula> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{0}$ </tex-math></inline-formula> is the free-space wavelength at the center frequency). Moreover, an overlapping bandwidth of 7.6% is realized with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\vert S_{11}\vert &lt; -10$ </tex-math></inline-formula> dB, gain variation less than 3 dB. This work may provide useful references for designing dual-polarized endfire antennas with stable radiation patterns, high gain, and compact size.

A Substrate-Integrated Waveguide Leaky-Wave Antenna Based on Eye-Shaped Transverse Slot

At present, there are few reports of broadside antennas based on the transverse slots in SIWs, because those slot structures often exist as open stopbands (OSB), which restrict radiation in the broadside direction. In this communication, a new type of transverse slot element, eye-shaped transverse slot element with a high phase shift, is proposed. The phase constant of this element can vary linearly, which can lead to continuous beam scanning from the backward-to-forward direction. The relationship between the phase difference and the element size is obtained by simulation. What is more, a leaky-wave antenna with element spacing slightly larger than half-waveguide wavelength is described, and its internal field distribution is analyzed. The measured results show that the main beam can scan from −56° to 39° when the frequency increases from 9.1 to 13 GHz, while the gain ranges from 9 to 11.7 dBi in the passband with an effective length of 110 mm. Because of its small antenna length, wide beam scanning range, and high gain, the antenna can be widely used in wireless communication or radar systems.

T-type folded SIW-based leaky-wave antennas with wide scanning angle and low cross-polarization

Abstract In this paper, a leaky-wave antenna (LWA) with wide scanning angle and low cross-polarization is proposed based on a T-type folded substrate-integrated waveguide (FSIW). Transverse slots with a sinusoidal distribution pattern are etched on the surface of the FSIW so that transmission lines with slow-wave characteristics can excite and radiate −1 order harmonics. The length of the transverse slot affects the dispersion characteristics of the transmission line, and the sinusoidal modulation period controls the operating range of the LWA. In the frequency range of 8.3–15 GHz, the proposed LWA achieves a wide scanning ranging from backward −42° to forward +68° continuously. The cross-polarization of the beam is also kept at less than −30 dB during this scanning. A prototype is fabricated and measured to confirm the design, and the measured results show an agreement with the simulated one.

A Wideband Compact Magnetoelectric Dipole Antenna Fed by SICL for Millimeter Wave Applications

A wideband compact magnetoelectric (ME) dipole antenna is investigated for millimeter-wave applications. First, an aperture coupled ME dipole is proposed with wideband and low profile. Next, transverse slots are added to miniaturize the antenna. The radiation performance of the higher-order mode is also improved. The antenna is finally miniaturized to 2.5×3.3 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ( 0.27 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.35 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> , where λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the wavelength in free space at center frequency) when it is used in the array environment. A bandwidth of 48.8% (24.3-40 GHz) for SWR <; 2 can be achieved, with unidirectional radiation performance over the operating band. By combining the proposed compact antenna with an eight-way substrate integrated coaxial line (SICL) feed network, a 1 ×8 linear array is designed, fabricated, and measured. Good beam scanning capability is also verified by active simulation. With the advantages of wide bandwidth, compact size, promising radiation pattern and wide-angle beam scanning potential, the proposed antenna would be attractive for millimeter-wave devices and antenna in package (AiP) applications.

A continual backward‐to‐forward beam scanning periodic microstrip leaky‐wave antenna with highly stable gain

AbstractA limitation of the traditional periodic leaky‐wave antennas (P‐LWAs) is the existence of the open‐stopband (OSB) with the antenna gain greatly reduced at broadside. In this paper, a novel periodic microstrip LWA with highly stable gain is proposed and the OSB is eliminated, realizing continual backward‐to‐forward beam scanning. The unit cell of the proposed antenna consists of a transversal slot, a narrow transversal slot and two intersecting oblique slots, as well as a metallic via. By adding a narrow transversal slot and adjusting the inclination of the oblique slots, the antenna gain keeps stable while it is operating. A prototype is proposed and analyzed, achieving continual backward‐to‐forward main‐beam scanning from 8 to 10.2 GHz. The main‐beam scans from −35° to +30° with the maximum gain of 11.36 dBi, and the antenna gain of 11.05 dBi is obtained at broadside at 9.3 GHz with no significant degradation. The variation value of the gain is less than 0.66 dB while the main‐beam is scanning from −28° to +15° near the broadside, indicating that the antenna gain is highly stable.

Design of Compact Transverse Slot Array Antenna Using Corrugated H plane Horn

Design of Compact Transverse Slot Array Antenna Using Corrugated H plane Horn