Open Access
High saturation photocurrent THz waveguide-type MUTC-photodiodes reaching mW output power within the WR3.4 band
(Optica, 2023) Grzeslo, Marcel; Dülme, Sebastián; Clochiatti, Simone; Neerfeld, Tom; Haddad, Thomas; Lu, Peng; Tebart, Jonas; Makhlouf, Sumer; Biurrun Quel, Carlos; Fernández Estévez, José Luis; Lackmann, Jörg; Weimann, Nils; Stöhr, Andreas; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
In this paper, we report on waveguide-type modified uni-traveling-carrier photodiodes (MUTC-PDs) providing a record high output power level for non-resonant photodiodes in the WR3.4 band. Indium phosphide (InP) based waveguide-type 1.55 µm MUTC-PDs have been fabricated and characterized thoroughly. Maximum output powers of −0.6 dBm and −2.7 dBm were achieved at 240 GHz and 280 GHz, respectively. This has been accomplished by an optimized layer structure and doping profile design that takes transient carrier dynamics into account. An energy-balance model has been developed to study and optimize carrier transport at high optical input intensities. The advantageous THz capabilities of the optimized MUTC layer structure are confirmed by experiments revealing a transit time limited cutoff frequency of 249 GHz and a saturation photocurrent beyond 20 mA in the WR3.4 band. The responsivity for a 16 µm long waveguide-type THz MUTC-PD is found to be 0.25 A/W. In addition, bow-tie antenna integrated waveguide-type MUTC-PDs are fabricated and reported to operate up to 0.7 THz above a received power of −40 dBm.
Open Access
Photonic-assisted 2-D terahertz beam steering enabled by a LWA array monolithically integrated with a BFN
(Optica, 2022) Haddad, Thomas; Biurrun Quel, Carlos; Lu, Peng; Tebart, Jonas; Sievert, Benedikt; Makhlouf, Sumer; Grzeslo, Marcel; Teniente Vallinas, Jorge; Río Bocio, Carlos del; Stöhr, Andreas; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
A novel photonic-assisted 2-D Terahertz beam steering chip using only two tuning elements is presented. The chip is based on an array of three leaky wave antennas (LWAs) with a monolithically integrated beamforming network (BFN) on a 50 µm-thick indium phosphide substrate. The THz beam angle in elevation (E-plane) is controlled via optical frequency tuning using a tunable dual-wavelength laser. An optical delay line is used for azimuth (H-plane) beam control. The simulated beam scanning range is 92° in elevation for a frequency sweep from 0.23 THz to 0.33 THz and 69.18° in azimuth for a time delay of 3.6 ps. For the frequency range from 0.26 THz to 0.32 THz, it is confirmed experimentally that the THz beam scans from −12° to +33°, which is in good agreement with the numerical simulations. The beam direction in azimuth scans with a total angle of 39° when applying a delay difference of 1.68 ps. A good agreement is found between theoretically predicted and experimentally determined THz beam angles with a maximum angle deviation below 5°. The experimental scanning angles are limited due to the mechanical constraints of the on-wafer probes, the on-chip integrated transition and the bandwidth of the THz receiver LNA. The mechanical limitation will be overcome when using a packaged chip.
Open Access
Development of a microscopic driver-centric simulator with Unity3D and SUMO
(2016) Biurrun Quel, Carlos; Serrano Arriezu, Luis Javier; Olaverri Monreal, Cristina; Escuela Técnica Superior de Ingenieros Industriales y de Telecomunicación; Telekomunikazio eta Industria Ingeniarien Goi Mailako Eskola Teknikoa; University of Applied Sciences Technikum Wien (Austria)
Diversas herramientas han sido desarrolladas en el campo de la simulación de tráfico. Estas herramientas permiten recrear situaciones de tráfico complejas de una forma realista, que pueden ser empleadas en la planificación de sistemas de transporte o para evaluar comunicaciones V2V (Vehículo a vehículo) en situaciones reales de tráfico. A pesar de que ciertos trabajos han sido llevados a cabo en el campo de la representación 3D de las simulaciones de tráfico, no existen demasiados ejemplos de plataformas Driver-Centric (con perspectiva del conductor) en los que el comportamiento del resto de vehículos es modelado por un simulador de tráfico. En este Trabajo Fin de Grado se presenta la elaboración de un simulador de tráfico Driver-Centric, capaz de emplear redes de carreteras reales junto con modelos de tráfico realistas, en un escenario 3D. Una librería existente en Java ha sido traducida a .NET y usada en Unity3D para implementar el protocolo TraCI y lograr la comunicación con el programa de simulación microscópica de tráfico, SUMO. Finalmente, se ha evaluado el funcionamiento del simulador y se han presentado futuras líneas de trabajo.
Open Access
Suppressing open stopband for terahertz periodic microstrip leaky-wave antennas
(IEEE, 2023) Haddad, Thomas; Biurrun Quel, Carlos; Lu, Peng; Kaya, Hacer; Mohammad, Israa; Stöhr, Andreas; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
This paper reports on a periodic microstrip Leaky-wave antenna (LWA). The open stopband issue is suppressed by altering the unit cell using a matching stub. The developed LWA is based on a grounded InP-substrate of 50 µm and has been fabricated and characterized between 0.23 to 0.33 THz. The dispersion diagram of the designed unit cell shows enhancement of the attenuation constant at the broadside frequency of 0.273 THz and about 50% less deflection at the broadside region on the Bloch impedance curves, consequently better impedance matching at the input. The simulated scattering parameters of the proposed LWA show that the return loss S11 is below 17 dB except for the broadside, which has a value of 13.8 dB. Furthermore, the beam steering capabilities of the antenna are simulated in the WR3.4 band and confirmed experimentally between 0.26 and 0.33 THz proving the beam direction to steer from −12° to +33°, respectively.
Open Access
Hyperbolic lens antenna in groove gap waveguide technology at sub-millimeter waves
(IEEE, 2022) Pérez Quintana, Dayan; Biurrun Quel, Carlos; Ederra Urzainqui, Íñigo; González-Ovejero, David; Beruete Díaz, Miguel; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
In this paper, a flat hyperbolic lens antenna using Groove Gap Waveguide (GGW) technology is designed at 300 GHz. A GGW horn antenna is used to feed the metamaterial lens placed in a parallel plate waveguide (PPW), in order to increase the directivity in the direction of propagation. The combination of both devices, the metalens and the GGW antenna, achieves excellent radiation performance.
Open Access
Feeder system design for OLAF SAR instrument
(IEEE, 2022-04-11) Biurrun Quel, Carlos; García-García, Quiterio; Río Bocio, Carlos del; Institute of Smart Cities - ISC
The design of the feeding system for the focal array in OLAF (Over-Lapped Sub-Array Fed) antenna for SAR Instrument at L-Band is presented. The proposed design consists of a circular patch with a balanced excitation all of it embedded in a ground plane which is connected to the lower ground plane by some shorting pins, reducing the mutual coupling with the neighbour radiating elements of the focal array. The balanced excitation has been implemented with a 180° hybrid using the differential input port. Dual polarization is achieved by using two 180° hybrids within the same layer. The stringent requirements for the system, namely low in cross-polarization, high isolation between the two polarizations (both below the-25dB reference level) and azimuthal symmetry of the radiation pattern are fulfilled within all the working bandwidth.
Open Access
Hybrid analog-digital SAR instrument with reflector antenna and overlapped subarray feed for earth observation
(IEEE, 2021) García, Quiterio; Orgaz, Lara; Castillo, Javier del; Toso, Giovanni; Imbembo, Ernesto; Biurrun Quel, Carlos; Río Bocio, Carlos del; Memeletzoglou, Nafsika; Institute of Smart Cities - ISC
As part of the European Space Agency (ESA) studies of new instrument for Earth observation, the design of a synthetic aperture radar (SAR) architecture based on overlapped array antennas was launched last year. The objective of the activity is to develop a test unit of a reflector based SAR antenna fed by an array organized in overlapped subarrays, supporting novel multichannel wide-swath SAR architectures, and exploiting multiple beams in both azimuth and range/elevation directions. In the letter, a hybrid analog/digital beamforming on reception with analog beamforming approach on transmission is analyzed. The antenna system consists of a large oversize reflector with a feedarray capable of generating multiple beams on receive for digital processing. In the letter, a description of the hybrid SAR Instrument is presented, describing the characteristics of the system, the antenna, the considered feedarray options and the main characteristics and system performances.
Open Access
Impedance modelling for high frequency unitraveling-carrier photodiodes
(IEEE, 2021) Grzeslo, Marcel; Biurrun Quel, Carlos; Stöhr, Andreas; Institute of Smart Cities - ISC
High-speed photodiodes stand out as potential candidates to enable next-generation communication systems working as mmWave/THz sources due to their intrinsic broadband behaviour. Impedance matching is an essential task in microwave engineering that enables an efficient delivery of the power generated by the source (i.e. photodiode) to the load (i.e. antenna). In this work, we analyse the impedance of a generic uni-travelling carrier photodiode and its dependency with frequency, bias voltage and other operational parameters. In addition, we present some calculations and use cases, highlighting the importance of properly matching this impedance in an actual system.
Open Access
New coplanar waveguide based on the gap waveguide technology
(IEEE, 2021) Biurrun Quel, Carlos; Teniente Vallinas, Jorge; Río Bocio, Carlos del; Institute of Smart Cities - ISC
A new planar waveguide, coined Inverted coplanar gap waveguide is presented. The concept of gap waveguides and parallel plate suppression between perfect magnetic and a perfect electric conductors is applied to coplanar waveguides in order to create a low-dispersion, low-loss transmission line. The combination of an artificial magnetic conductor and channelized top cover allow the propagation of an even coplanar mode with a strong component propagating over the air while solving encapsulation matters without the use of metallic vias. The main theory behind this new concept is presented and supported by FEM simulations on a commercial software package.
Open Access
Multi-channel feedarray reflector antenna based radar concept for HRWS SAR imaging
(IEEE, 2021) Castillo, Javier del; Orgaz, Lara; García, Quiterio; Memeletzoglou, Nafsika; Toso, Giovanni; Imbembo, Ernesto; Biurrun Quel, Carlos; Río Bocio, Carlos del; Institute of Smart Cities - ISC
Large deployable reflector based multi-channel antenna systems are a key component of next generation SAR missions as they allow implementing multi-beam imaging capabilities and provide an efficient way to overcome the classical SAR resolution-coverage trade-off, covering wide swaths with high azimuth resolution. The presented work shows the design of a multichannel L-band SAR system and antenna architecture based on different feeders concepts and capable to map 400 km ground swath with 5 meter spatial resolution in dual polarization. The paper describes a preliminary design and architecture of the SAR system and the antenna where different design aspects including beamforming concepts and feedarray implementation techniques have been identified and assessed in view of achieving the required SAR performances while reducing the overall complexity of the solution.