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Author

Marc Imbert

Bio: Marc Imbert is an academic researcher from Polytechnic University of Catalonia. The author has contributed to research in topics: Flat lens & Antenna (radio). The author has an hindex of 5, co-authored 14 publications receiving 152 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the performance of three different inhomogeneous gradient-index dielectric lenses with the effective parameters circularly and cylindrically distributed is evaluated in terms of radiation pattern parameters, maximum gain, beam scanning, bandwidth performance, efficiencies, and impedance matching in the whole frequency band of interest.
Abstract: This paper presents the design, low-temperature co-fired ceramics (LTCC) fabrication, and full experimental verification of novel dielectric flat lens antennas for future high data rate 5G wireless communication systems in the 60 GHz band. We introduce and practically completely evaluate and compare the performance of three different inhomogeneous gradient-index dielectric lenses with the effective parameters circularly and cylindrically distributed. These lenses, despite their planar profile antenna configuration, allow full 2-D beam scanning of high-gain radiation beams. A time-domain spectroscopy system is used to practically evaluate the permittivity profile achieved with the LTCC manufacturing process, obtaining very good results to confirm the viability of fabricating inhomogeneous flat lenses in a mass production technology. Then, the lenses performance is evaluated in terms of radiation pattern parameters, maximum gain, beam scanning, bandwidth performance, efficiencies, and impedance matching in the whole frequency band of interest. Finally, the performance of the three lenses is also experimentally evaluated and compared to a single omni-directional antenna and to a ten-element uniform linear array of omni-directional antennas in real 60 GHz wireless personal area network indoor line-of-sight (LOS) and obstructed-LOS environments, obtaining interesting and promising remarkable results in terms of measured received power and root-mean-square delay spread. At the end of this paper, an innovative switched-beam antenna array concept based on the presented cylindrically distributed effective parameters lens is also introduced and completely evaluated, confirming the potential applicability of the proposed antenna solution for future 5G wireless millimeter-wave communication system.

64 citations

Journal ArticleDOI
TL;DR: In this paper, a novel inhomogeneous gradient-index dielectric flat lens for millimeter-wave applications is presented, which leads to a low-cost, low-profile, and lightweight antenna solution, easy to integrate in a compact millimeter wave wireless communication system.
Abstract: In this letter, a practical fabrication of a novel inhomogeneous gradient-index dielectric flat lens for millimeter-wave applications is presented. A previous theoretical design of a dielectric flat lens composed of different permittivity materials is now modeled and analyzed for a practical prototype fabrication and performance evaluation at 60 and 77 GHz. The measurement results at 60 GHz show that with the novel gradient-index dielectric flat lens antenna prototype, we can achieve up to 18.3 dB of broadside gain, beam-steering capabilities in both planes from $-30^\circ$ to $+30^\circ$ with around 15 dB of gain, and up to $\pm 45^\circ$ with around 14 dB of gain, with low sidelobe levels. At 77 GHz, the performance evaluation shows that we can obtain up to 18.9 dB of broadside gain, beam-steering capabilities in both planes from $-30^\circ$ to $+30^\circ$ with around 17 dB of gain and low sidelobe levels, and up to $\pm 45^\circ$ with around 15 dB of gain. This novel design leads to a low-cost, low-profile, and lightweight antenna solution, easy to integrate in a compact millimeter-wave wireless communication system.

61 citations

Journal ArticleDOI
TL;DR: In this paper, a broadband patch antenna capable of covering the entire IEEE 802.11ad (WiGig) frequency band (57-66 GHz) is presented, where a conductor-backed (CB) coplanar waveguide (CPW)-fed loop slot couples the energy to the patch antenna, resulting in a broad bandwidth.
Abstract: The design, microfabrication, and characterization of a broadband patch antenna capable of covering the entire IEEE 802.11ad (WiGig) frequency band (57–66 GHz) are presented in this letter. A conductor-backed (CB) coplanar waveguide (CPW)-fed loop slot couples the energy to the patch antenna, resulting in a broad bandwidth. The feed circuitry along with the loop is formed on a quartz substrate ( $\varepsilon_{\rm r} = 3.9, \tan \delta = 0.0002$ at 60 GHz), on top of which an SU-8-based three-dimensional (3-D) structure with air cavities is microfabricated. The patch metallization is deposited on top of this 3-D structure. While the main role of the structure made out of SU-8 material is to provide a mechanical support for the patch metallization, the antenna takes advantage of the air cavities underneath, thus resulting in an antenna substrate with a very low loss. This, in turn, improves the overall antenna performances. The simulated and measured impedance characteristics agree well, showing ${\sim}15\hbox{\%}$ bandwidth. Also, the radiation pattern results demonstrate the integrity of radiation pattern with reasonably constant gain values (average ${\sim}6.4~$ dB) in the broadside direction over the entire WiGig band.

18 citations

Proceedings ArticleDOI
07 Jul 2013
TL;DR: In this paper, a dielectric flat lens antenna with scanning capabilities from -30° to +30° with around 20 dB gain in the whole entire band of interest (57 to 66 GHz), and up to ±60° of beam-steering capabilities with around 15 dB of gain.
Abstract: In this paper we present the design of a dielectric flat lens antenna to operate in the 60 GHz band for WPAN applications. In order to overcome the specific atmospheric attenuation, which characterizes the propagation in the 60 GHz band, high directive antennas are required. Moreover, due to high user random mobility in indoor environments, beam-steerable antennas are also needed. For these reasons, we propose a design based on a dielectric flat lens antenna with scanning capabilities from -30° to +30° with around 20 dB of gain in the whole entire band of interest (57 to 66 GHz), and up to ±60° of beam-steering capabilities with around 15 dB of gain. The dielectric flat lens also leads to low-profile antenna configuration, easy to manufacture and low-cost, in order to integrate the design together with a commercial RF CMOS chip.

9 citations

Journal ArticleDOI
TL;DR: In this article, a metamaterial spacer composed of spiral resonators and narrow metal strips was tested to operate like a bidirectional artificial magnetic conductor (AMC) reflector at 2.45 GHz.
Abstract: A metamaterial spacer composed of spiral resonators (SRs) and narrow metal strips has been tested to operate like a bidirectional artificial magnetic conductor (AMC) reflector at 2.45 GHz. The performance of the spacer has also been evaluated in a closely spaced multiple-antenna system applied to successfully increase the transmission capacity of a commercial wireless IEEE 802.11b router.

6 citations


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Journal ArticleDOI
TL;DR: In this article, a 3D-printed Luneburg lens with a simplified geometry is presented, where rod-type structures are employed as the unit cell of the gradient-index material to realize the required permittivity distribution in the lens.
Abstract: A 3-D-printed Luneburg lens with a novel simplified geometry is presented. The rod-type structures are employed as the unit cell of the gradient-index material to realize the required permittivity distribution in the lens. A prototype designed in the Ka -band is manufactured successfully by using a commercial 3-D printing facility. The substrate-integrated waveguide fed magnetoelectric (ME)-dipole antenna with endfire radiation is introduced as the feed for the Luneburg lens due to its wideband performance and compact configuration. By combining the lens with a set of the ME-dipoles, a millimeter-wave (mm-wave) multibeam Luneburg lens antenna is designed, fabricated, and measured. An overlapped impedance bandwidth of wider than 40% that can cover the entire Ka -band and mutual coupling below −17 dB are verified by the fabricated prototype. Nine stable radiation beams with a scanning range between ±61°, gain up to 21.2 dBi with a variation of 2.6 dB, and radiation efficiency of around 75% are achieved as well. With the advantages of good operating features, low fabrication costs, and ease of integration, the proposed multibeam Luneburg lens antenna would be a promising candidate for the fifth-generation (5G) mm-wave multiple-input multiple-output (MIMO) applications in 28 and 38 GHz bands.

115 citations

Journal ArticleDOI
TL;DR: In this article, a flat compact dual-polarized Luneburg lens antenna is proposed and implemented using the printed-circuit-board-stacked gradient-index metamaterials for beam scanning and multibeam applications at X-bands.
Abstract: Based on a transformation optics method, a flat compact dual-polarized Luneburg lens antenna is proposed and implemented using the printed-circuit-board-stacked gradient-index metamaterials for beamscanning and multibeam applications at X-bands. The transformed material properties of the planar Luneburg lens are designed with 17-layered permittivity distribution of polynomials. Each layer is discretized into $41 \times 41$ pixels made of broadband and less polarization-dependent unit cells responsible for desired index distributions. The effects of transformation, approximation, and discretization on the lens performance are analyzed comprehensively. Also, to validate the implementation method, a flat Luneburg lens with a thickness of 14.1 mm, a focal length of 28 mm, and an aperture size of $98.9 \times 98.9$ mm2 is designed and tested. A stacked aperture-coupled patch antenna operating at 10 GHz is applied as a feeder. The measured results show that the proposed antenna can operate over a bandwidth of ~20% with an antenna efficiency of 32%, a cross-polarization level of <−17.1 dB, as well as the maximum gain of 15.9/16.35 dBi and a scanning angle of ±32°/±35° for two orthogonal polarizations, respectively. The presented flat Luneburg lens antenna featuring broad bandwidth, high gain, wide scanning angle, and easy fabrication has a high potential in 5G wireless communication, imaging, and remote sensing applications.

115 citations

Journal ArticleDOI
TL;DR: This letter presents a low-cost printed circuit board (PCB)-based dual-band antenna for future wireless local area network (WLAN) applications that is designed to fully cover both WiFi channels and Wireless Gigabit Alliance channels.
Abstract: This letter presents a low-cost printed circuit board (PCB)-based dual-band antenna for future wireless local area network (WLAN) applications. The antenna is designed to fully cover both WiFi channels (2.4/5.2/5.8 GHz) and Wireless Gigabit Alliance (WiGig) channels (57-64 GHz). At the WiFi frequency bands, the antenna is based on a printed monopole, while at the WiGig frequency band, a wideband higher-order-mode patch antenna is adopted. A compact microstrip resonance cell (CMRC) low-pass filter is also designed to allow feeding the monopole antenna at WiFi frequency bands while isolating the monopole from the patch for WiGig operation. The design is fabricated by standard PCB and plated-through-hole technologies, and its performance is validated by measurement.

104 citations

Journal ArticleDOI
TL;DR: In this article, the authors presented the complete design of a wideband transmit-array (TA) antenna with high gain and high efficiency for D-band applications based on the low-temperature co-fired ceramic technology.
Abstract: This paper presents the complete design of a wideband transmit-array (TA) antenna with high gain and high efficiency for D-band applications based on the low-temperature co-fired ceramic technology. The proposed unit cell is composed of a pair of wideband magnetoelectric dipoles as the receive/transmit elements, together with a substrate-integrated waveguide (SIW) aperture-coupling transmission structure for independent phase adjustability. A 360° phase coverage is obtained by the proposed phasing element, and its phase response curves are nearly parallel within a broad frequency band, which indicates a wideband performance. To verify the design, the fabricated prototype is measured by using a vector network analyzer in a terahertz compact-range anechoic chamber. The measured peak gain is 33.45 dBi at 150 GHz with the aperture efficiency of 44.03%, and the measured 3 dB gain bandwidth is 124–158 GHz (24.29%). The good radiation performance ensures that the proposed SIW aperture-coupling TA antenna is a promising candidate for D-band applications.

100 citations

Journal ArticleDOI
TL;DR: In this paper, a novel circularly polarized (CP) antenna element based on spiral antenna is proposed, which can achieve 23.0% impedance bandwidth and 21.9% 3-dB axial ratio (AR) bandwidth with a maximum gain of 7.9 dB.
Abstract: A novel circularly polarized (CP) antenna element based on spiral antenna is proposed in this paper. It is differentially fed with an aperture through two vias locating at opposite sides of the aperture. This element can be easily integrated with the low loss substrate integrated waveguide and fabricated with the low cost printed circuit board technology. It can achieve 23.0% impedance bandwidth and 21.9% 3-dB axial ratio (AR) bandwidth with a maximum gain of 7.9 dBic. In order to broaden the AR bandwidth and lower the AR values of the antenna array, sequential rotation is applied to make a 2 × 2 subarray. The subarray covers an impedance bandwidth of 21.3%, with AR values lower than 1.1 dB across the whole impedance matching band. Thereafter, by employing the designed subarray, a 4 × 8 antenna array is composed and fabricated. The measured impedance bandwidth covers 14.1%, from 56.55 to 65.13 GHz, and the measured 3-dB AR bandwidth covers 21.1%, from 55 to 68 GHz. The maximum measured gain is 19.5 dBic. It also demonstrates that the proposed antenna element is a promising candidate to design high gain CP antenna arrays in millimeter-wave band.

98 citations