Sökning: "spiral antenna"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden spiral antenna.

  1. 1. Characterization of artificially soft surfaces and their applications in antenna design

    Författare :Zhinong Ying; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dipole antenna; UTD; GPS; broadband antennas; circular polarization; feed; moment method; soft and hard surfaces; surface impeddance; corrugated horn; antennas; multipath effect; microstrip antenna; magnetic coating; spiral antenna; corrugated surface; dielectric loaded surface; ground plane; slot antenna; monopole antenna; helical antenna; choke-ring;

    Sammanfattning : .... LÄS MER

  3. 2. NbN and NbTiN Hot Electron Bolometer THz Mixers

    Författare :Pourya Khosropanah; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; receiver noise; hot electron bolometer; superconducting detector; spiral antenna; NbTiN; submillimeter mixer; THz mixer; HEB; FTS; NbN; quasioptical receiver; heterodyne receiver; double slot antenna; twin slot antenna; Fourier Transform Spectrometer;

    Sammanfattning : The thesis reports the development of Hot Electron Bolometer (HEB) mixers for radio astronomy heterodyne receivers in THz frequency range. Part of this work is the fabrication of HEB devices, which are based on NbN or NbTiN superconducting thin films (≤5 nm). They are integrated with wideband spiral or double-slot planar antennas. LÄS MER

  4. 3. Study of MgB2 and YBa2Cu3O7-x Microbolometers for THz Sensing Applications

    Författare :Stella Bevilacqua; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; THz Detectors; bolometers; IF bandwidth; YBa2< sub>Cu3< sub>O7-x< sub>; Terahertz frequency; HEB; MgB2< sub>; noise; superconductors;

    Sammanfattning : In this thesis, two novel THz detectors based on magnesium diboride (MgB2)and yttrium barium copper oxide (YBa2Cu3O7-x) are presented. In particular,MgB2 superconductor is used for the investigation of hot-electron bolometer(HEB) mixers, while YBa2Cu3O7-x is explored in microbolometers for room-temperaturecoherent and incoherent detection. LÄS MER

  5. 4. Superconducting THz mixers based on MgB2 film

    Författare :Stella Bevilacqua; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; bolometers; IF bandwidth.; superconductors; MgB2; THz Detectors; mixers;

    Sammanfattning : Superconducting NbN hot electron bolometer (HEB) mixers are widely used in terahertz radio astronomy. Such mixers have superior performance compared to SIS and Schottky diode mixers at frequency above 1THz. However, their drawback is a limited IF bandwidth. LÄS MER

  7. 5. Self-Switching Diodes for Zero-Bias Terahertz Detection

    Författare :Andreas Westlund; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; self-switching diode; noise-equivalent power; SSD; graphene; zero-bias; InAs; InGaAs; terahertz; detector;

    Sammanfattning : The self-switching diode (SSD) has been investigated as a potential terahertz detector in recent years. The SSD accomplishes a non-linear current-voltage relation through a field-effect, which enables detection at zero bias from microwave up to terahertz frequencies. In this work, SSDs were realised in two new materials; InAs and graphene. LÄS MER