Open Access
Compact bull's-eye antenna in ridge gap waveguide with circular polarization at 60 GHz
(IEEE, 2021) Pérez Quintana, Dayan; Ederra Urzainqui, Íñigo; Beruete Díaz, Miguel; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
In this work, a Bull's-Eye (BE) antenna with circular polarization (CP) based on ridge gap waveguide (RGW) technology, working in the millimeter-wave band (60 GHz) is numerically and experimentally demonstrated. The structure is coupled through a step transition to a ridge-line that ends in two orthogonal arms of different lengths to generate CP. The wave is coupled to the top plate by a central diamond slot surrounded by the BE structure, which consists of four concentric periodic corrugations around the slot. Simulations and experimental results are in good agreement, with practical bandwidth of 6.8% with respect to center frequency and peak gain of 18.4 dB. The antenna has right-handed CP (RHCP) with polarization discrimination of more than 30 dB.
Open Access
Low-sidelobe-level millimeter-wave asymmetric bull's eye antenna with minimal profile feeding
(IEEE, 2024) Navarro Cía, Miguel; Beaskoetxea Gartzia, Unai; Teniente Vallinas, Jorge; Beruete Díaz, Miguel; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
Bull’s eye antennas exhibit remarkable directivity considering their low profile, albeit accompanied by high sidelobes. This undesirable radiation characteristic is tackled here by reporting a complementary split ring feeding whereby the broadside space-wave partially responsible for the high sidelobes is cancelled while the leaky wave is excited effectively. This feeding results in an asymmetric bull’s eye antenna with minimal profile (∼ 0.73λ0) and no protrusions on the radiating interface. The fabricated 10-period antenna operating in the Ka-band shows a directivity of 23.5 dBi, a sidelobe level of −22.9 dB (>6 dB improvement compared to other bull’s eye antennas) and a beamwidth of 3.7◦ and 6.7◦ in the E- and H-plane, respectively.
Open Access
Bull’s-eye antenna with circular polarization at millimeter waves based on ridge gap waveguide technology
(IEEE, 2021) Pérez Quintana, Dayan; Ederra Urzainqui, Íñigo; Beruete Díaz, Miguel; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
In this communication, a Bull’s-Eye (BE) antenna with circular polarization (CP) based on ridge gap waveguide (RGW) technology is numerically and experimentally demonstrated. The structure is excited from the bottom with a standard WR-15 waveguide (V -band) coupled through a step transition to a ridgeline that ends in two orthogonal arms of different lengths to generate CP. Radiation is coupled to the top plate by a central diamond slot surrounded by the BE structure, which consists of four concentric periodic corrugations around the slot. Simulations and experimental results are in good agreement, with axial ratio below 1 dB at the operation frequency and peak gain of 18.4 dB. The antenna has right-handed CP (RHCP) with polarization discrimination of more than 30 dB.
Open Access
Ultrathin and high-efficiency Pancharatnam-Berry phase metalens for millimeter waves
(AIP Publishing, 2021) Moreno-Peñarrubia, Alexia; Teniente Vallinas, Jorge; Kuznetsov, Sergei A.; Orazbayev, Bakhtiyar; Beruete Díaz, Miguel; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
Applying the Pancharatnam–Berry (PB) principle to half-wave plate (HWP) metasurfaces allows the manipulation of wavefronts along with the conversion of the handedness of circularly polarized incident waves by simply rotating the meta-atoms that compose the metasurface. PB metasurfaces (PBM) working in transmission mode with four or more layers have been demonstrated to reach levels of transmission effi- ciency near 100% but also have resulted in bulky structures. On the other hand, compact tri-layer ultrathin (k/8) designs have reached levels near 90% but are more challenging than single- or bi-layer structures from a manufacturing viewpoint. Here, we propose a compact ultrathin (
Open Access
Reconfigurable millimeter-wave reflectarray based on low loss liquid crystals
(IEEE, 2024) Pérez Quintana, Dayan; Aguirre Gallego, Erik; Olariaga Jauregui, Eduardo; Kuznetsov, Sergei A.; Lapanik, Valeri I.; Sutormin, Vitaly S.; Zyryanov, Victor Ya; Marcotegui Iturmendi, José Antonio; Beruete Díaz, Miguel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
This article reports on the development and evaluation of a reconfigurable millimeter-wave reflectarray (RA) based on liquid-crystal (LC) substrate operating in the D-band (105–125 GHz). The RA is composed of a high-impedance surface (HIS) with a meta-array of 33 × 29 patches on a 2-mm-thick quartz substrate, separated from the ground plane (GP) by a 40-µm-thick LC layer. A novel LC composition with low dielectric losses (<0.003) and high dielectric anisotropy (>1.3) has been developed for operation at millimeter waves. The results demonstrate a reflection phase tunability of 210◦ and low insertion losses of 2.5 dB. Furthermore, the device was demonstrated as a proof of concept for 1-D beam-steering applications, exhibiting an operational bandwidth of 12 GHz.