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Funding Information: ACKNOWLEDGMENT This work was financially supported by the Academy of Finland under grant MilliRAD, number 314541. The authors would like to thank I. Huhtinen for the RF measurements. Publisher Copyright: © 2022 European Microwave Association. This paper describes a study of impact of different passivation methods on performance of gradient refractive index (GRIN) lenses. Three different passivation layers on top of lenses are studied: PolySi, PolySi and PECVD silicon oxide (PolySi+SiO2), and PECVD silicon oxide (SiO2). Antenna gains and radiation patterns of fabricated lenses are measured. The study shows that passivation methods have strong impact on silicon GRIN lenses performance. A model with a low-resistivity layer on top of high-resistivity Si can explain observed effects.

A portable electronic navigational aid (104) e.g. for the blind (102), comprising a radio frequency, preferably millimeter wave, radar (218) with at least one transmitting (TX) channel and a plurality of receiving (RX) channels, at least one orientation sensor (220) configured to obtain data indicative of the orientation of the radar, and a processing element (210) configured to adaptively control (500, 602) the beamforming of the radar based on the data provided by the orientation sensor. A corresponding method is presented. An accessory, such as a replaceable cover, containing a radio frequency radar for attaching to an electronic host device is presented.Patent family as of 18.11.2021AU2015316666 AA 20170427 AU20150316666 20150914 AU2015316666 BB 20200305 AU20150316666 20150914 CA2961290 AA 20170314 CA20152961290 20150914 CN107106400 A 20170829 CN201580061986 20150914 CN107106400 B 20210507 CN201580061986 20150914 DE602015061555 D1 20201119 DE201560061555T 20150914 EP3193810 A2 20170726 EP20150784967 20150914 EP3193810 B1 20201104 EP20150784967 20150914 JP2017533443 T2 20171109 JP20170534006T 20150914 JP2021113822 A2 20210805 JP20210071196 20150914 KR20170057340 A 20170524 KR20177010042 20150914 US11137490 BB 20211005 US20140487190 20140916 US2016077202 AA 20160317 US20140487190 20140916 WO16042203 A2 20160324 WO2015FI50602 20150914 WO16042203 A3 20160519 WO2015FI50602 20150914Link to current patent family on right

In this paper we present for the ?rst time an analytical electromechanical model for capacitive micromachined ultrasonic transducers (CMUTs) with multi-layered diaphragms of non-uniform thickness. The model is based on dynamical Kirchhoff plate theory, which allows to derive the accurate static de?ection and vibration mode, and hence the mechanical and electrical impedance of the transducer. Experimental veri?cation of the model is provided by measurements of electrical impedance and transmission in air. Resonant frequencies given by the model deviate less than 2 % from the measured results.

The first commercial automotive radars are designed for blind-spot detection, collision warning, and automatic cruise control. These radars, however, could be used for other applications as well, such as road condition classification,vulnerable road user detection, and data transfer from ubiquitous sensors or tags. This paper discusses automotive radar for road condition classification at 24 GHz and shows results of semipassive and active radar transponders at 77 GHz that could be used as ubiquitous sensors or tags in traffic applications.

Radio frequency identification has rapidly spread throughout the industry as a means to identify and track goods. In many cases, there's a need for measuring and logging of a physical quantity, e.g. temperature of a frozen food in the cold chain. However, as there's very limited power available for the RFID transponder, the integration of sensors is not a trivial task. In this presentation, the sensor powering and readout in RFID is discussed, especially in the case of passive and semipassive UHF RFID. First the the power transfer form the reader and backsacttering modulation are considered, as well as the power available for sensor readout. The fundamental trade-off between captured and scattered power is investigated. Second, different sensor readout electronics and strategies are compared to minimize power consumption. Third, examples of RFID sensor implementations are presented. The talk aspires to give a comprehensive glance at present UHF RFID sensors, and to illustrate the situations, where RFID sensors can and should be used.

This paper presents millimeter wave identification (MMID) concept, which extends the Radio frequency identification (RFID) systems to millimeter wave frequencies. The MMID system is described as well as experimental demonstrations are presented both at 60 GHz and 77 GHz.

Radio frequency identification (RFID) is an asymmetric radio protocol, where uplink communication (from transponder to reader) is implemented with backscattering modulation. The idea was first demonstrated in the 1940's. One of the first consumer applications of RFID was access control, and key cards based on an inductive near field coupling are widely used even today. The introduction of Schottky diodes to CMOS processes enabled passive RFID, i.e. transponders without a battery, at ultra high frequencies (UHF) with reasonable cost and read range in the end of 1990's. This has opened up new applications and inspired new research on RFID. This thesis studies the radio frequency (RF) components and general RF phenomena in RFID at UHF and millimetre waves. The theoretical analysis of the radio path reveals that the read range of a passive UHF system is ideally limited by the downlink, i.e. the power transfer from reader to the transponder. However, the architecture of the reader RF front end is critical, because the transmitted signal may couple a significant amount of noise to the receiver, overpowering the faint reflection from the transponder. In the thesis, two adaptive RF front ends are introduced to eliminate the noise coupling from the transmitter. One of the most critical problems with UHF RFID has been the detuning of transponder antennas on different mounting platforms. The detuning may significantly diminish the read range of the transponder, especially on metal surfaces. In this thesis, two backscattering-based measurement techniques for the transponder antennas are presented. The detuning effect has been studied using these measurement techniques, and a platform tolerantantenna is introduced. RFID at millimetre waves enables miniaturisation of the reader antenna, and widening the data bandwidth over short distances. This could be used to access wirelessly mass memories with wide data bandwidth. A semipassive or active transponder could communicate, e.g., with automotive radars. The millimetre wave identification (MMID) has been theoretically studied and experimentally verified at 60 GHz.

This research report is the final report of the project "Use of radio frequency identification technology for managing information concerning the recycling of electrical and electronic equipment (ETEK)" carried out between 1 March 2003 and 28 February 2005. The project was a part of the Streams research programme of Tekes, the National Technology Agency of Finland. The recycling process is a challenging environment with regard to the application of RFID technology. Among other things, the metal contained in the products and collection containers made of metal imposes technical obstacles for the detection of RFID tags. Due to this, the applicability of RFID technology to recycling was studied both in laboratory conditions and in production environments at recycling facilities. RFID equipment operating on frequencies of 13.56 MHz and 869 MHz was used in the studies. The subject of the study was the identification of display units and metallic collection containers. The identification of display units was studied in an industrial environment at the Kuusakoski Oy disassembly line, and the identification of collection containers at Ekokem Oy. The most important advantages of RFID technology identified in the project include product identification and association with the producer in any phase of the waste treatment process, precise distribution of costs among producers, the possibility for automatic sorting of products, availability of product information, improved efficiency of material flows, automation and improved efficiency of information management, and improved efficiency of collection container management.

Etätunnisteisiin perustuvien sovellusten määrä kasvaa nopeasti. Passiivisten etätunnistimien edullisuus ja ympäristöystävällisyys tukevat niiden menekkiä tulevaisuudessa useilla yhteiskunnan osa-alueilla, myös liikenteessä. Liikenteessä RFID-teknologiaa voidaan käyttää usealla eri tavalla. Saattomuisti tai lukijalaite voivat olla ajoneuvossa, tienvarressa, tiessä, matkapuhelimessa, kuljetusvälineessä tai pakkauksessa. Lukutapahtuma saattomuistin ja lukijalaitteen välillä voidaan toteuttaa joko ajoneuvosta tienvarteen tai tienvarresta ajoneuvoon aina tarpeen mukaan. Tulevaisuudessa kussakin ajoneuvossa voisi olla passiivinen tunniste ja kussakin matkapuhelimessa lukijalaite. Tienvarteen voitaisiin asentaa sekä tunnisteita että lukijalaitteita. RF-TIE-projektin tavoitteena oli selvittää, kuinka lukutapahtuma onnistuu maantieolosuhteissa ja -nopeuksilla. Tieympäristössä ongelmia aiheuttavat mm. ajoneuvojen nopeudet, vaihtelevat olosuhteet sekä antennien sijoittaminen ja suuntaus. Tutkimus tarkasteli kahden ratkaisun toimivuutta: 1) etätunnistimet ovat ajoneuvossa ja lukijat väylän vierellä, päällä tai sisällä ja 2) etätunnistimet ovat väylärakenteessa ja lukijat ajoneuvoissa. Teknisenä tavoitteena oli selvittää antenniratkaisujen sekä lähetin- ja vastaanotinyksiköiden toimivuus kenttäolosuhteissa. Ensimmäisessä vaiheessa selvitettiin, mihin etätunniste on ajoneuvossa sijoitettava, jotta lukutapahtuma on mahdollinen. Muovipuskurin sisälle sijoitettu tunniste kyettiin lukemaan yli 2 metrin etäisyydeltä, vaikka antenneja ei ollut erityisesti modifioitu tällaiseen tarkoitukseen ja käytettiin nykyisin sallittua 0,5 watin lukutehoa. Tällainen etätunnisteen sijoitus soveltuu ajoradan reunasta luettavaksi. Myös tuulilasiin sijoitetun tunnisteen lukeminen onnistui, tällainen sijoitus sopii esimerkiksi portaalista tapahtuvaan lukemiseen. Seuraavaksi testattiin menetelmän toimivuus todellisissa olosuhteissa. Vaikka laitteistoa ei vielä ollut viritetty erityisesti tähän tarkoitukseen, osa lukutapahtumista onnistui jopa 100 km/h -nopeudella, tosin vain 1 metrin etäisyydeltä. Lisäksi kokeiltiin tiehen sijoitettujen etätunnistimien toimivuutta. Asfaltin alle soran sisälle noin 15 cm:n syvyyteen sijoitetut etätunnisteet kyettiin lukemaan. Sen sijaan jo 1 cm:n vesikerros asfaltin päällä teki lukemisen mahdottomaksi. Lopuksi kokeita täydennettiin 2 W lukutehon sallivalla laitteistolla, mutta ilmeisesti käytettävissä olleiden laitteiden ja komponenttien yhteensopivuusongelmat ja laatuvaihtelut antoivat osittain vaihtelevia tuloksia mittausten välille. Tekniikka osoittautui toimivaksi liikenteen olosuhteissa, joten tutkimuksen jatkoksi on mahdollista käynnistää erilaisia sovelluskokeiluja. Lupaavimpia sovelluksia lienevät liikenteen seurannan ja valvonnan palvelusovelluksia mahdollistavat käyttökohteet kuten autojen katsastustarrat, joukkoliikenteen seuranta, kevyen liikenteen opastus, pysäköintipaikkojen varaus, maksaminen ja opastus sekä liikennevirran seuranta.