60-GHz Single-Layer Slot-Array Antenna fed by Groove Gap Waveguide

[EN] A V-band single-layer low-loss slot-array antenna is presented in this letter. Radiating slots are backed by coaxial cavities, which are fed through a groove gap waveguide E-plane corporate feed network. Cavity resonances are created by shortening nails with respect to the surrounding ones. This fact enables a compact single-layer architecture since coaxial cavities and feeding network can share the same bed of nails. A 16 x 16 array is designed, constructed, and measured to demonstrate the viability of this concept for high-gain single-layer slot-array antennas. In addition, this solution can be extended to circular polarization by seamlessly adding a polarizer above the slots without changing the feeding network piece. Measurements show a relative bandwidth of 10% with input reflection coefficient better than -10 dB and a mean antenna efficiency above 70% within the operating frequency band (57-66 GHz).This work was supported by the Spanish Ministry of Economy and Competitiveness under Project TEC2016-79700-C2-1-R.Ferrando-Rocher, M.; Valero-Nogueira, A.; Herranz Herruzo, JI.; Teniente, J. (2019). 60-GHz Single-Layer Slot-Array Antenna fed by Groove Gap Waveguide. IEEE Antennas and Wireless Propagation Letters. 18(5):846-850. https://doi.org/10.1109/LAWP.2019.2903475S84685018

Dual Circularly Polarized Aperture Array Antenna in Gap Waveguide for High-Efficiency Ka-Band Satellite Communications

[EN] A novel fully metallic Ka-band dual circularly polarized antenna array is presented in this contribution. It consists of 64 circular apertures (8x8) and it is implemented in gap waveguide technology. The antenna includes 4 layers, which are completely metallic, leading to a highly efficient performance. The experimental results confirm reflection coefficient values lower than -10 dB from 29 GHz to 31 GHz as well as stable radiation patterns throughout the whole frequency range. Good average axial ratio (AR) of 1.5 dB has been measured in the working band for both polarizations. Measured directivity is 28 dBi and antenna efficiency keeps close to 80%.This work was supported by the Spanish Ministry of Economy and Competitiveness (Ministerio de Economía y Competitividad) under Project TEC2016-79700-C2-1-R.Ferrando-Rocher, M.; Herranz Herruzo, JI.; Valero-Nogueira, A.; Bernardo-Clemente, B. (2020). Dual Circularly Polarized Aperture Array Antenna in Gap Waveguide for High-Efficiency Ka-Band Satellite Communications. IEEE Open Journal of Antennas and Propagation. 1:283-289. https://doi.org/10.1109/OJAP.2020.3001087S283289

Full-Metal K-Ka Dual-Band Shared-Aperture Array Antenna Fed by Combined Ridge-Groove Gap Waveguide

© 2019 IEEE. Personal use of this material is permitted. Permissíon from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertisíng or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.[EN] This letter presents an 8 x 8 dual-band shared-aperture array antenna operating in K-(19.5-21.5 GHz) and Ka-band (29-31 GHz) using gap waveguide technology. Radiating elements consist of circular apertures located on the top plate of the antenna and excited by two stacked cavities with different diameters for dual-frequency operation. A waffle grid is used on top to increase the effective area of apertures and reduce grating lobes. Each stacked cavity is fed by its appropriate corporate-feeding net-work: The upper feeding layer operates at 20 GHz band, and the lower one at 30 GHz band. As a result, the antenna presents two ports, one for each band, which radiate a directive far-field pattern with linear polarization, orthogonal to each other. Experimental results show impedance and radiation pattern bandwidths larger than 1.5 GHz in both bands.This work was supported by the Spanish Ministry of Economics and Competitiveness under Project TEC2016-79700-C2-1-R.Ferrando-Rocher, M.; Herranz Herruzo, JI.; Valero-Nogueira, A.; Bernardo Clemente, B. (2019). Full-Metal K-Ka Dual-Band Shared-Aperture Array Antenna Fed by Combined Ridge-Groove Gap Waveguide. IEEE Antennas and Wireless Propagation Letters. 18(7):1463-1467. https://doi.org/10.1109/LAWP.2019.2919928S1463146718

Performance Assessment of Gap Waveguide Array Antennas: CNC Milling vs. 3D Printing

(c) 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.[EN] This letter focuses on comparing manufacturing features of three-dimensional (3-D) printing techniques versus conventional computer numerical control (CNC) milling in the context of gap waveguide technology. To this end, a single-layer array antenna has been designed as a demonstrator. The antenna under test, intended for Ka-band, is composed of 8 x 8 radiators fed by a gap-waveguide (GW) corporate network. Two identical prototypes have been manufactured, but each applying a different fabrication technique, i.e., 3-D printing and CNC milling. The experimental results of both antennas are presented, under the same conditions and measurement facilities. The conclusions drawn in this letter provide a valuable assessment of 3-D-printing viability for GW arrays against the conventional milling technique.This work was supported by the Spanish Ministry of Economy and Competitiveness (Ministerio de Economia y Competitividad) under Grant TEC2016-79700-C2-1-R.Ferrando-Rocher, M.; Herranz Herruzo, JI.; Valero-Nogueira, A.; Bernardo Clemente, B. (2018). Performance Assessment of Gap Waveguide Array Antennas: CNC Milling vs. 3D Printing. IEEE Antennas and Wireless Propagation Letters. 17(11):2056-2060. https://doi.org/10.1109/LAWP.2018.2833740S20562060171

Grating Lobes Reduction Using a Multilayer Frequency Selective Surface on a Dual-Polarized Aperture Array Antenna in Ka-Band

[EN] This paper presents a multilayer frequency selective surface for a dual-polarized aperture array antenna in Ka-band. The elements of the array are cylindrical open cavities with a diameter of at 30 GHz, and spaced one wavelength. Due to this separation between elements, which is limiting and not reducible by the architecture of the feeding network and the size of the radiating element, grating lobes appear. Frequency Selective Surfaces (FSS) can be a solution to this problem without modifying the feeder architecture nor the radiating elements. This paper presents the FSS design for reducing grating lobes level, the antenna assembly, and the experimental validation. The full antenna performance demonstrates that FSS operates in a range identical to the feeder (29.5 GHz to 31 GHz) with the added benefit of reducing the grating lobes level more than 10 dB for both polarizations.This work was supported by the Spanish Ministry of Economy and Competitiveness (Ministerio de Economia y Competitividad) under Project TEC2016-79700-C2-1-R.Sánchez-Escuderos, D.; Ferrando-Rocher, M.; Herranz Herruzo, JI.; Valero-Nogueira, A. (2020). Grating Lobes Reduction Using a Multilayer Frequency Selective Surface on a Dual-Polarized Aperture Array Antenna in Ka-Band. IEEE Access. 8:104977-104984. https://doi.org/10.1109/ACCESS.2020.3000069S104977104984

Periodic Leaky-Wave Antenna on Planar Goubau Line at Millimeter-Wave Frequencies

A periodic leaky-wave antenna on a planar Goubau line is presented. This transmission line is formed by a planar single-wire waveguide on a thin dielectric substrate. Leakage is produced by adding dipoles along the line on the bottom face of the substrate. A coplanar waveguide is used to feed the antenna, which acts as a smooth transition between the input coaxial cable and the planar Goubau line. The advantage of using this line lies on its losses, lower than those of typical microstrip lines due to the absence of a ground plane. As a result, a higher radiation efficiency than in microstrip-fed antennas can be obtained while keeping similar advantages, e.g., low profile or low production cost. A prototype of the antenna at 40 GHz has been fabricated. Measurements of this prototype are presented in this letter.This work was supported by the Spanish Ministry of Education and Science (Ministerio de Educacion y Ciencia) under Projects TEC2010-20841-C04-01 and CSD2008-00068.Sánchez Escuderos, D.; Ferrando Bataller, M.; Herranz Herruzo, JI.; Cabedo Fabrés, M. (2013). Periodic Leaky-Wave Antenna on Planar Goubau Line at Millimeter-Wave Frequencies. IEEE Antennas and Wireless Propagation Letters. 12:1006-1009. https://doi.org/10.1109/LAWP.2013.2278035S100610091

Untilted narrow-wall slots excited by parasitic dipoles in groove-gap waveguide technology

© 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This work describes a new way to excite untilted slots in the narrow wall of a rectangular waveguide. The radiating structure consists of an inclined parasitic dipole located within the waveguide, parallel to narrow wall, and close to the untilted slot. Furthermore, the rectangular waveguide is advantageously replaced by a groove gap waveguide so that nonwraparound resonant slots can be used. The concept is discussed in detail and demonstrated experimentally through a linear arrayThis work was supported in part by the Spanish Ministerio de Economia y Competitividad under project TEC2013-47360-C3-3P.Herranz Herruzo, JI.; Valero-Nogueira, A.; Martínez Giner, S.; Vila Jiménez, A. (2015). Untilted narrow-wall slots excited by parasitic dipoles in groove-gap waveguide technology. IEEE Transactions on Antennas and Propagation. 63(11):4759-4765. https://doi.org/10.1109/TAP.2015.2478144S47594765631

Mechanical phase shifter in gap-waveguide technology

[EN] This contribution presents a low-loss mechanical phase shifter in gap-waveguide technology. The phase shifter is aimed at ground terminals for Ka-band satellite on-the-move applications. The use of the gap-waveguide technology allows to divide the device into two main blocks distributed in two levels: a lower-rotatable block, in charge of the power distribution and the phase shifting; and an upper-fixed block with the output waveguides. In this paper, the lower and upper blocks are designed using Groove-gap waveguides (GGW), and Ridge-gap waveguides, respectively, connected to each other by coupling slots. Results show a good performance within the operating frequency band in terms of the phase shift between consecutive output ports (suitable for array feeding), and the return loss level at the input port.This work has been supported by the Spanish Ministry of Science, Innovation and Universities (Ministerio de Ciencia, Innovacion y Universidades) under project TEC2016-79700- C2-1-R.Sánchez-Escuderos, D.; Herranz Herruzo, JI.; Ferrando-Rocher, M.; Valero-Nogueira, A. (2020). Mechanical phase shifter in gap-waveguide technology. IEEE. 1-5. https://doi.org/10.23919/EuCAP48036.2020.9135719S1

Dual Circularly-Polarized Slot-Array Antenna in Ka-Band fed by Groove Gap Waveguide

[EN] A dual circularly-polarized slot-array antenna fed by a Groove Gap Waveguide (GGW) and operating in the KaBand is presented in this paper. A simple mechanism is proposed to switch the polarization, from RHCP to LHCP, and viceversa. The lid of the antenna has two pieces: one fixed and one sliding. The fixed piece hosts T-shaped slots, and the sliding block is in charge of adjusting the offset of the perpendicular grooves with respect to the longitudinal slots. Preliminary results show an axial ratio below 1.5 dB for both, RHCP and LHCP, within a bandwidth of 1 GHz centered at 30 GHz.This work has been supported by the Spanish Ministry of Science, Innovation and Universities (Ministerio de Ciencia, Innovacion y Universidades) under project TEC2016-79700-C2-1-R.Ferrando-Rocher, M.; Herranz Herruzo, JI.; Sánchez-Escuderos, D.; Valero-Nogueira, A. (2020). Dual Circularly-Polarized Slot-Array Antenna in Ka-Band fed by Groove Gap Waveguide. IEEE. 421-422. https://doi.org/10.1109/IEEECONF35879.2020.9329473S42142

Single-Layer Circularly-Polarized Ka-Band Antenna Using Gap Waveguide Technology

(c) 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this[EN] A single-layer circularly polarized array antenna is proposed in the context of the so-called gap waveguide (GW) technology. This ultra-compact antenna combines the corporate feeding network and the radiating apertures over one single layer, standing out among other solutions proposed so far in this technology. Apertures are backed by chamfered cylindrical cavities and are fed through a corporate feeding network, which combines both groove and ridge GWs. Cavities are naturally integrated within the bed of nails hosting grooves and ridges, leading to a very low-profile 4×4 array. Experimental results are presented to confirm the good radiation performance obtained by simulations. The proposed array architecture may be seamlessly enlarged to any size thanks to the scalability of the gap-based corporate feeding network, making this solution very attractive for medium to high-gain applications.This work was supported by the Spanish Ministry of Economics and Competitiveness under Project TEC2013-47360-C3-3-P and Project TEC2016-79700-C2-1-R.Ferrando-Rocher, M.; Herranz Herruzo, JI.; Valero-Nogueira, A.; Vila Jiménez, A. (2018). Single-Layer Circularly-Polarized Ka-Band Antenna Using Gap Waveguide Technology. IEEE Transactions on Antennas and Propagation. 66(8):3837-3845. https://doi.org/10.1109/TAP.2018.2835639S3837384566