Substrate Integrated Waveguide Cavity-backed Antenna Research Articles

A Typical Slotted SIW Cavity-backed Antenna for Dual frequency operations in U-NII Bands

A low profile circular shaped cavity-backed substrate integrated waveguide (SIW) antenna with two-typical intersecting rectangular slots on the ground plane is designed to operate in the dominant TM010 mode at a frequency of 5.19 GHz in U-NII-1 band for wireless applications. The initially designed antenna produces a gain of 4 dBi with a narrow impedance bandwidth extending from 5.17 – 5.22 GHz. The antenna design is further modified by insertion of another shifted two-typical intersecting rectangular slots to finally resemble that of Hash shape; resulting in dual band antenna operation at 4.9 and 5.93 GHz. The gains obtained are 3.7 dBi and 1.4 dBi for 4.9 and 5.93 GHz respectively with an impedance bandwidth covering 4.88 - 4.92 GHz and 5.92 – 5.94 GHz respectively. The antenna prototype is fabricated using Arlon AD270 substrate material. Parametric studies are performed in terms of return loss and gain of the antenna. All simulations are carried out using HFSS v19.0 and show similar behavior to their experimentally measured counterparts.

Single-Layer, Dual-Port, and Dual-Mode Antenna With High Isolation for WBAN Communications

In this letter, a single-layer, dual-port, and dual-mode antenna with high isolation between the ports is suggested. This antenna consists of a short-circuited ring patch antenna that surrounds a substrate integrated waveguide (SIW)-based circular cavity in the center. An annular-ring slot is etched on the upper surface of the circular cavity and constitutes a cavity-backed annular ring slot antenna. Dimensions of the antenna are chosen in a way that TM₂₁ mode and TM₁₁ mode are placed at the frequency of 5.8 GHz for the short-circuited ring patch antenna and SIW cavity-backed antenna, respectively; the former has an omnidirectional radiation pattern and the latter has a broadside radiation pattern. Due to having two rows of vias, one for the short-circuited ring patch antenna and the other for SIW cavity-backed antenna, the isolation between the two ports is excellent owing to reduced surface waves. The measurement results of a fabricated prototype are properly consistent with the simulation results. This antenna is an appropriate option to be used in wireless body area networks for having simple structure, dual-mode, single-frequency, and high isolation.

Planar SIW cavity-backed antenna loaded with slots for multiband operations

A low-profile substrate integrated waveguide (SIW) cavity-backed antenna loaded with slots is presented for multiband operations. This antenna is designed by loading a rectangular and square-shaped slot onto a rectangular SIW cavity for multiband radiation. The slots are created inside the rectangular cavity to induce a hybrid mode (i.e. $${\text{TE}}_{110} + {\text{TE}}_{120}$$ ), which supports to radiate a lower resonance frequency. The rectangular slot is used to excite $${\text{TE}}_{120}$$ mode at 5.21 GHz, while square-shaped slot excites hybrid mode at 2.21 GHz. This hybrid mode is obtained by coupling the cavity modes $${\text{TE}}_{110}$$ and $${\text{TE}}_{120}$$ through the metallized via-holes. The designed antenna yields multiband response owing to resonant slots when governed by the inset microstrip feedline. The operating modes are explained with the help of mode theory mechanism. The fabricated antenna comprises with dimensions 30 $$\times$$ 30 $$\times$$ 1.6 mm3, which is printed on a low-cost Flame Retardant-4 dielectric substrate. To verify the simulated counterparts, the fabricated antenna has been tested, which offers a fractional bandwidth of 6.9% (2.10–2.25 GHz) in the hybrid mode at 2.18 GHz, 8.4% (3.35–3.64 GHz) in the $${\text{TE}}_{110}$$ mode at 3.45 GHz and 10.8% (5.04–5.61 GHz) in the $${\text{TE}}_{120}$$ mode at 5.26 GHz with suitable far-field pattern.

Design and analysis of dual dumbbell and rectangular slots SIW cavity-backed antenna at 2.45 GHz

The design and realization of a wideband substrate-integrated waveguide (SIW) cavity-backed slot antenna operating at 2.45 GHz for WLAN applications are presented. Dual dumbbell-shaped slots with rectangular slots are used to achieve increased bandwidth. The bandwidth observed is 160 MHz with the dumbbell-shaped slots. Further, it has been improved up to 9.2% by adding a rectangular slot. The wideband antenna is analyzed using ANSYS HFSS and fabricated on FR-4 substrate. The measured results of the proposed design are in good agreement with the simulation results and comparable with the reported results.

Miniaturization and Bandwidth Enhancement of Quarter-mode and Half-mode SIW Cavity-Backed Antenna for 5G Applications

Substrate Integrated Waveguide (SIW) is a special antenna technology which retains reduced copper surface waves and low dielectric loss property of classical rectangular waveguides. The antennas developed on SIW have simple configuration with an ease of fabrication in flame redundant wearable and integration in walls and floors. In this sense a Quarter-mode SIW (QMSIW) antenna has been designed, analyzed and its performance has been compared with Half-mode SIW. QMSIW has been precisely designed to operate efficiently in the range of 40 - 57 GHz. It aims at enhancing the bandwidth for 5G applications with a maximum return loss of -36 db at 55 GHz. HMSIW structure has Triple band resonant frequencies at 20.5 GHz, 24.7 GHz & 27 GHz with the return loss values of -34 db, -14 db & -32.5 db respectively. Both antennas operate in 20 – 72 GHz range of 5G applications.

Wideband millimeter-wave substrate integrated waveguide cavity-backed antenna for satellites communications

This paper presents a new type of wideband waveguide (SIW) cavity-backed patch antenna for millimeter wave (mmW). The antenna proposed applies to applications of 31-36 GHz Ka-band such as satellites communications. The SIW is intended with settings for particular slots. The antenna is constructed on Rogers RT5880 (lossy) with 2.2 dielectric constant, l.27 mm thickness, and 0.0009 loss tangent. It is simulated in the programming of computer simulation technology (CST) Microwave Studio. The simulated results show that the SIW antenna resonates across 31 to 36 GHz bands, which means that this new antenna covers all applications within this range. The reflection coefficients in targeting range are below 10 dB. The antenna achieves good efficiency and gain with 80% and 8.87 dBi respectively.

Dual-Band Wide-Angle Scanning Phased Array Composed of SIW-Cavity Backed Elements

In this communication, an aperiodic dual-band phased array with wide-angle scanning performance is presented. A substrate integrated waveguide cavity-backed antenna, which has wide beamwidths at 4.8 and 5.8 GHz, is used as the basic array element. The phased array contains eight subarrays with an equally spaced arrangement, and each subarray is arranged in a symmetric structure. Theoretical and optimization methods, in which the main beams of the subarray and the full array are coincident and the maximum sidelobe of the full array points to the null of the subarray, are proposed for sidelobe reduction. Based on the optimized results, the main beam of the phased array can scan from −75° to +75° at both the frequency bands, and the array supports the 3 dB beam coverage from −86° to +86° at the low-frequency band and from −82° to +82° at the high band, respectively. The phased array is simulated, fabricated, and measured. The measured results validate its wide-angle scanning performance.

Increasing the bandwidth of cavity-backed SIW antennas by using stacked cavities

AbstractThis paper presents a technique to increase the bandwidth in substrate integrated waveguide (SIW) cavity-backed antennas, inspired by the design of cavity filters. The proposed structure consists of a slot antenna backed by two cavities, located one on top of the other and coupled through a slot. To demonstrate the bandwidth increase, a standard cavity-backed SIW antenna, with a rectangular slot etched in the top metal plane, has been designed, manufactured, and measured. Subsequently, a similar antenna was developed, by doubling the substrate thickness with the aim to improve the bandwidth. Finally, the new topology of two-cavity SIW antenna has been implemented and compared with the two previous ones. Simulation and experimental results show that the proposed two-cavity antenna exhibits a bandwidth twice as large as the standard SIW cavity-backed antenna.

Bandwidth Enhancement of Substrate Integrated Waveguide Cavity-backed Bow-tie-complementary-ring-slot Antenna using a Shorted-via

In this study, a planar cavity-backed bow-tie-complementary-ring-slot antenna is proposed, and a new approach for bandwidth enhancement using a shorted-via is introduced. A shorted-via concept overcomes the narrow impedance bandwidth of a conventional substrate integrated waveguide cavity-backed antenna. By adjusting the location of the shorted-via (placed just above the centroid of the radiating slot), the individual bandwidth of the lower and higher order resonances has been tuned below -10 dB criterion, which results in the broadening of the bandwidth. Finally, the antenna is proficient to operate for an impedance bandwidth of 15.71 per cent, ranging from 12.02~14.07 GHz. The proposed antenna shows a gain of better than 4 dBi within the operating band with less than 0.5 dBi variation. Moreover, the antenna preserves good radiation characteristics, which is similar to that of the conventional metallic counterpart. To validate the simulated results, an antenna is fabricated and tested. The simulated results in terms of the reflection coefficient, gain, and radiation patterns are in good agreement with the measured results.

A Novel Manufacturing Process for Compact, Low-Weight and Flexible Ultra-Wideband Cavity Backed Textile Antennas.

A novel manufacturing procedure for the fabrication of ultra-wideband cavity-backed substrate integrated waveguide antennas on textile substrates is proposed. The antenna cavity is constructed using a single laser-cut electrotextile patch, which is folded around the substrate. Electrotextile slabs protruding from the laser-cut patch are then vertically folded and glued to form the antenna cavity instead of rigid metal tubelets to implement the vertical cavity walls. This approach drastically improves mechanical flexibility, decreases the antenna weight to slightly more than 1 g and significantly reduces alignment errors. As a proof of concept, a cavity-backed substrate integrated waveguide antenna is designed and realized for ultra-wideband operation in the [5.15–5.85] GHz band. Antenna performance is validated in free space as well as in two on body measurement scenarios. Furthermore, the antenna’s figures of merit are characterized when the prototype is bent at different curvature radii, as commonly encountered during deployment on the human body. Also the effect of humidity content on antenna performance is studied. In all scenarios, the realized antenna covers the entire operating frequency band, meanwhile retaining a stable radiation pattern with a broadside gain above 5 dBi, and a radiation efficiency of at least 70%.

A Passive Circularly Polarized Van Atta Reflector For Vehicle Radar Applications

This letter proposes a planar passive circularly polarized (CP) retrodirective antenna (RDA) array for vehicle radar applications. Different than the linearly polarized RDA arrays, the retrodirective signal generated by the CP RDA arrays can easily be extracted due to the orthogonal polarized character of the scattering and retrodirective signals. Circular polarization is achieved by a substrate integrated waveguide cavity-backed antenna. Moreover, the low-loss and nondispersive substrate integrated coaxial lines are employed as the feeding networks to expand the operating bandwidth for the large array. Measured results of bistatic and monostatic radar cross section verify the designed prototype, showing that the CP RDA array covers a scan angle of at least ±30° from boresight without interference by sidelobes. The measured bandwidth of the retrodirective property is 24.85-25.45 GHz. The capability of CP retrodirectivity ensures that the proposed RDA array is a good candidate for short-range vehicle radio equipment.

340-GHz SIW Cavity-Backed Magnetic Rectangular Slot Loop Antennas and Arrays in Silicon Technology

A 340-GHz on-chip antenna (OCA) with high-gain and high-radiation efficiency is designed using a standard ${0}.{13}\hbox{-}\upmu {\rm m}$ SiGe BiCMOS technology without any postprocesses. In the proposed OCA structure, a rectangular slot loop is etched in the upper wall of a substrate integrated waveguide (SIW) to form a magnetic current loop radiator. The SIW structure forms a back cavity to suppress the surface waves and separate the radiation aperture from the low-resistivity substrate. Furthermore, the side wall of the SIW cavity and the edge of the slot form a ${{{\lambda }}_{{g}}}/4$ resonator to reflect the power back to the slot loop. As a result, the radiation efficiency is improved. By etching a slot properly in the SIW upper wall, another resonating point is constructed and hence, the bandwidth is broadened. Single antenna element and a ${2} \times {2}$ array are both designed and fabricated with- and without- the slot structure; a maximum gain of 7.9 dBi with the radiation efficiency of 48% at 340 GHz is achieved for the proposed SIW cavity-backed antenna structure.

Bandwidth-enhanced SIW cavitybacked antenna array using even and odd modes

A novel technique to enhance the bandwidth of substrate-integrated waveguide (SIW) cavity-backed antenna array is presented. The proposed array consists of four SIW cavities connected by inductive windows as feeding network and four wide slots on the surface of each cavity as radiating part. The even–odd mode theory is used to analyse the array. By offsetting the slots from the cavities centre, two different work modes are excited at two resonant frequencies simultaneously and the bandwidth enhancement is achieved by merging them together. A prototype is fabricated to verify the properties of the array. The measured bandwidth can be broadened to 14.5% from 18.25 to 21.1 GHz and the maximal gain can reach up to 12.8 dBi.

Design of a Compact High-Efficiency Circularly Polarized Monopulse Cavity-Backed Substrate Integrated Waveguide Antenna

A novel compact monopulse cavity-backed substrate integrated waveguide (SIW) antenna is proposed. The antenna consists of an array of four circularly polarized (CP) cavity-backed SIW antennas, three dual-mode hybrid coupler, and three input ports. $\mathrm{TE}_{{10}}$ and $\mathrm{TE}_{{20}}$ modes are excited in the dual-mode hybrid to produce sum and difference patterns, respectively. The antenna is modeled with a fast full-wave hybrid numerical method and also simulated using full-wave Ansoft HFSS. The whole antenna is integrated on a two-layer dielectric with the size of ${42}\;\mathrm{mm} \times 36\;\mathrm{mm}$ . A prototype of the proposed monopulse antenna at the center frequency of 9.9 GHz is manufactured. Measured results show $- {10}\hbox{-}\mathrm{dB}$ impedance bandwidth of 2.4%, 3-dB axial ratio (AR) bandwidth of 1.75%, 12.3-dBi gain, and $- {28}\hbox{-}{\mathrm{dB}}$ null depth. The proposed antenna has good monopulse radiation characteristics, high efficiency, and can be easily integrated with planar circuits.

Design of a Compact Circularly Polarized Dual-Mode Monopulse Cavity-Backed Substrate Integrated Waveguide Antenna

A novel compact dual-mode monopulse cavity-backed substrate integrated waveguide (SIW) antenna is proposed. The antenna consists of an array of two circular-polarized cavity-backed SIW antennas, a dual-mode section, and two input ports. ${\rm TE}_{10}$ and ${\rm TE}_{20}$ modes are excited in the multimode section to produce sum and difference pattern, respectively. A prototype of the proposed monopulse antenna at the center frequency of 10 GHz is manufactured. Measured results show 10-dB return-loss bandwidth of 4.4%, axial-ratio bandwidth of 1.9%, 9.2 dBi gain, and 25 dB null depth. The proposed antenna has good monopulse radiation characteristics and can be easily integrated with planar circuits.

Novel SIW Cavity-Backed Antenna Array Without Using Individual Feeding Network

Substrate integrated waveguide (SIW) cavity-backed antenna arrays have advantages of low-profile, high-gain and low-cost fabrication. However, traditional SIW cavity-backed antenna arrays usually load with extra feeding networks, which make the whole arrays larger and more complex. A novel 4 × 4 SIW cavity-backed antenna array without using individual feeding network is presented in this letter. The proposed antenna array consists of sixteen SIW cavities connected by inductive windows as feeding network and wide slots on the surface of each cavity as radiating part. Without loading with extra feeding network, the array is compact.