Morphological microwave imaging has shown interesting results on reconstructing biological objects inside the human body, and these parameters represent their actual biological condition, but not their biological activity. In this paper, we propose a novel microwave technique to locate the low-frequency ($f\simeq 1$ kHz) -modulated signals produced by a microtag mimicking an action potential and proved it in a cylindrical phantom of the brain region. A set of two combined UWB microwave applicators, operating in the 0.5 to 2.5 GHz frequency band and producing a nsec interrogation pulse, is able to focus its radiated field into a small region of the brain containing the microtag with a modulated photodiode. The illuminating UWB microwave field was first modulated by the low-frequency ($f\simeq 1$ kHz) electrical signal produced by the photodiode, inducing modulated microwave currents into the microtag that reradiating back towards the focusing applicators. At the receiving end, the low-frequency ($f\simeq 1$ kHz) -modulated signal was first extracted from the full set of the backscattered signals, then focused into the region of interest and spatially represented in the corresponding region of the brain, resulting in a spatial resolution of the images in the order of 10 mm.

Microwaves have proven their imaging capabilities to visualize the body composition for medical applications thanks to their penetration inside biological structures. In this context, this paper presents a novel methodology that aims to extract not just the internal morphology but also the brain’s functional activity using the UWB Pulse Amplitude Modulation (PAM) technique to have simultaneously functional monitoring and imaging capability and apply it to monitor the Parkinson’s disease. The radiofrequency system is composed of two orthogonal sets of double UWB probes operating in the frequency range of 0.5 GHz - 1.5 GHz. An experimental set-up has been devised that avoids complex in-vivo testing, albeit allows a system proof-of-concept validation. A bio-tag consisting of an optically modulated photodiode is used to emulate local medium changes associated to cell activity. The proposed system is used to first extract the modeled brain Action Potential (AP) to validate the performance of the bio-tag, and then to monitor the Parkinson’s disease (PD) based on the beta frequency band character within basal ganglia–thalamocortical (BGTC) which is a key marker for the PD. The results show a good capability of locating and differentiating the signals generated within the phantom by the bio-tag, alternatively emulating the healthy and PD’s state, based on the frequency. The obtained results of the functional monitoring technique on distinguishing the healthy from non-healthy brain model activity, as well as in the phantom mimicking the average proprieties of a human head, will serve as a basis for detecting functional diseases in the future.

The need for non-ionizing techniques for medical imaging applications has led to the use of microwave signals. Several systems have been introduced in recent years based on increasing the number of antennas and frequency bandwidth to obtain high resolution and good accuracy in locating objects. A novel microwave imaging system that reduces the number of required antennas for precise target location appropriate for medical applications is presented. The proposed system consists of four UWB extended gap ridge horn (EGRH) antennas covering the frequency band from 0.5 GHz to 1.5 GHz mounted on a cylindrical phantom that mimics the brain in an orthogonal set of two EGRH probes. This configuration has the ability to control both the longitudinal and transversal dimensions of the reconstructed target’s image, rather than controlling the spatial resolution, by increasing the frequency band that can be easily affected by medium losses. The system is tested numerically and experimentally by the detection of a cylindrical target within a human brain model.

The ability to utilize resources to meet the need of growing diversity of communication services and user behavior marks the future of cognitive wireless communication systems. Cognitive wireless technologies for vehicular communications, in combination with Orbital Angular Momentum (OAM) modes aim at extending Non-Line-Of-Sight (NLOS) short-distance communications for smart mobility. In this regard, OAM antenna frameworks need to be developed to support these technologies. In this work, we describe a magnetoelectric dipole antenna framework supporting OAM modes. The framework is derived from moment tensors of specific vector spherical harmonic functions synthesized from dipoles. The antenna framework is discussed in terms of OAM generation, and it is validated numerically and experimentally for l = 1 OAM mode, achieving more than 500MHz operation bandwidth at the frequency of operation of 3.5GHz. Also, for l = 1 OAM mode, the null aligns precisely with the anticipated dimensions numerically computed.

In this paper a Double Ridge Waveguide (DRW) antenna fed by a microstrip line covering a frequency band from 0.5GHz to 2.5GHz is designed, fabricated, and measured, for functional microwave imaging. The proposed DRW antenna is used as the probe element in a collateral multi-static system to detect a cylindrical target located inside a human brain liquid medium. Also an approach for the spatial reconstruction accuracy based on maximum time resolution is presented. Measured and simulated results are conducted and discussed.

(English) The use of microwave imaging techniques in medical applications has gained significant interest because of its non-ionizing character, low cost, and body penetrability. Different techniques and systems for microwave imaging have been successfully developed and tested for the diagnosis and monitoring of different parts of the human body to detect certain diseases by means of determining their complex permittivity distribution representing the electrical biological condition. This thesis proposes to open a new avenue adding to the previous biological condition imaging capabilities some trace of its biological activity. With this goal, a novel microwave technique oriented to locate and detect the low-frequency signals approaching the functional activity of a certain biological organ. These electrical signals, responsible for the different biological phenomena, are normally identified as action or membrane potential. Due to their low-frequency character (f ≃ 1 kHz), they stay mostly confined inside the human body and different kinds of contact electrodes are normally employed to measure them. In this work, we propose a novel technique to extract (from the inside of the human body) and wirelessly monitor these low-frequency signals (generated by a number of basic microorganisms as cells or bacteria mimicking the activity of the organ under study) based on the use of an illuminating microwave signal. Differently from the low-frequencies, the microwave signals are able to propagate inside (in and out) of the human body, being focused (with a Ultra-Wideband (UWB) - 0.5 to 2.5 GHz- multi-probe geometry) on a specific zone, and eventually becoming affected (modulated) by the low-frequency functional biological signals. Once extracted (de-modulated) from the interrogative microwave signal, the information of the action potential signal representing the functional activity, is spatially located inside the region of interest using a microwave differential imaging technique. In this work it has been specifically studied, the capability of monitoring localized action potential signals in the brain representing a Parkinson’s disease (PD), characterized by electrical signals generated in the subthalamic nucleus (STN) and the globus pallidus (GPi) with specific action potential patterns. Three main points have been developed: * Design of an optimized imaging geometry consisting of four (sequentially Tx and Rx) UWB Extended Gap Ridge Horn (EGRH) antennas disposed on two orthogonal sets. * Design of an UWB-Pulse Amplitude Modulation (PAM) monitoring system producing a nsec interrogation pulse * Modeling and validation of the UWB Microwave Functional Brain Activity Extraction for Parkinson’s Disease Monitoring concept. (Català) L'ús de tècniques d'imatge de microones en aplicacions mèdiques ha guanyat un interès important pel seu caràcter no ionitzant, el seu baix cost i la seva penetrabilitat corporal. S'han desenvolupat i provat amb èxit diferents tècniques i sistemes d'imatge per microones per al diagnòstic i seguiment de diferents parts del cos humà per detectar determinades malalties mitjançant la determinació de la seva complexa distribució de permitivitat que representa la condició biològica elèctrica. Aquesta tesi proposa obrir una nova via afegint a les capacitats anteriors d'imatge de la condició biològica algun rastre de la seva activitat biològica. Amb aquest objectiu, una nova tècnica de microones orientada a localitzar i detectar els senyals de baixa freqüència que s'acosten a l'activitat funcional d'un determinat òrgan biològic. Aquests senyals elèctrics, responsables dels diferents fenòmens biològics, s'identifiquen normalment com a potencial d'acció o de membrana. A causa del seu caràcter de baixa freqüència (f ≃ 1 kHz), es mantenen majoritàriament confinats dins del cos humà i normalment s'utilitzen diferents tipus d'elèctrodes de contacte per mesurar-los. En aquest treball, proposem una nova tècnica per extreure (des de l'interior del cos humà) i controlar sense fil aquests senyals de baixa freqüència (generats per una sèrie de microorganismes bàsics com cèl·lules o bacteris que imiten l'activitat de l'òrgan en estudi) basat en sobre l'ús d'un senyal il·luminador de microones. A diferència de les baixes freqüències, els senyals de microones són capaços de propagar-se dins (dins i fora) del cos humà, enfocant-se (amb una banda ultraampla (UWB) - 0,5 a 2,5 GHz- geometria multi-sonda) en una determinada zona, i finalment es veu afectada (modulada) pels senyals biològics funcionals de baixa freqüència. Un cop extreta (desmodulada) del senyal interrogatiu de microones, la informació del senyal de potencial d'acció que representa l'activitat funcional, es localitza espacialment dins de la regió d'interès mitjançant una tècnica d'imatge diferencial de microones. En aquest treball s'ha estudiat específicament, la capacitat de monitoritzar senyals de potencial d'acció localitzats al cervell que representen una malaltia de Parkinson (MP), caracteritzada per senyals elèctrics generats al nucli subtalàmic (STN) i al globus pàl·lid (GPi) amb acció específica. patrons potencials. S'han desenvolupat tres punts principals: * Disseny d'una geometria d'imatge optimitzada que consta de quatre antenes UWB Extended Gap Ridge Horn (EGRH) (seqüencialment Tx i Rx) disposades en dos conjunts ortogonals. * Disseny d'un sistema de monitorització de modulació d'amplitud de pols (PAM) UWB que produeix un pols d'interrogació nsec * Modelització i validació del concepte UWB Microwave Functional Brain Activity...