Showing papers on "Extremely high frequency published in 2009"

Synthesis of an electromagnetic wave absorber for high-speed wireless communication.

Abstract: Millimeter waves (30-300 GHz) are starting to be used in next generation high-speed wireless communications. To avoid electromagnetic interference in this wireless communication, finding a suitable electromagnetic wave absorber in the millimeter wave range is an urgent matter. In this work, we prepared a high-performance millimeter wave absorber composed of a series of aluminum-substituted epsilon-iron oxide, epsilon-Al(x)Fe(2-x)O(3), nanomagnets (0 < or = x < or = 0.40) with a particle size between 25 and 50 nm. The materials in this series have an orthorhombic crystal structure in the Pna2(1) space group, which has four nonequivalent Fe sites and Al ion that predominantly occupies the tetrahedral [FeO(4)] site. The field-cooled magnetization curves showed that the T(C) values were 448, 480, and 500 K for x = 0.40, 0.21, and 0, respectively. The magnetization versus external magnetic field showed that the coercive field H(c) values at 300 K were 10.2, 14.9, and 22.5 kOe for x = 0.40, 0.21, and 0, respectively. The millimeter wave absorption properties were measured at room temperature by terahertz time domain spectroscopy. The frequencies of the absorption peaks for x = 0.40, 0.30, 0.21, 0.09, 0.06, and 0 were observed at 112, 125, 145, 162, 172, and 182 GHz, respectively. These absorptions are due to the natural resonance achieved by the large magnetic anisotropies in this series. Such frequencies are the highest ones for magnetic materials. Because aluminum is the third most abundant atom, aluminum-substituted epsilon-iron oxide is very economical, and thus these materials are advantageous for industrial applications.

A 340–380 GHz Integrated CB-CPW-to-Waveguide Transition for Sub Millimeter-Wave MMIC Packaging

Abstract: In this letter, a rectangular waveguide to conductor backed-coplanar waveguide electromagnetic transition suitable of operating at sub-millimeter wave frequencies is demonstrated. The dipole based transition is fabricated using InP monolithic microwave integrated circuit technology. The compact transition eliminates wire-bonding problems (return loss and insertion loss) and is suitable for direct integration of sub-millimeter wave monolithic integrated circuits. Measured transition loss of ~1 dB has been achieved in the frequency range of 340 to 380 GHz.

A continuously tunable and filterless optical millimeter-wave generation via frequency octupling.

Abstract: This work proposes a cost-effective, continuously tunable and filterless optical millimeter-wave (MMW) signal generation employing frequency octupling. Optical MMW signals with 30-dB undesired sideband suppression ratios can be obtained. Since no optical filtering is required, the proposed system can be readily implemented in wavelength-division-multiplexing (WDM) systems. V-band 60-GHz and W-band 80-GHz optical MMW signals are experimentally demonstrated. Because of the high undesired sideband suppression ratio, 60-GHz waveform with 50% duty cycle is observed. The single-sideband (SSB) phase noise of the generated 60-GHz signal is -73 dBc/Hz at 10 kHz. The proposed system is a viable solution for the future ultra-high frequency MMW applications up to 320 GHz using the external modulator with a limited bandwidth of 40 GHz.

Millimeter wave radar for remote measurement of vital signs

Abstract: We present the development of a 228 GHz heterodyne radar system for the remote measurement of respiration and heart rates. The advantages of a millimeter wave system include a higher sensitivity to small displacements, transmission through the atmosphere and clothing and the ability to maintain a collimated beam over large distances. We present a set of respiration and heart rate measurements out to a range of 50 meters.

Photonic vector signal generation at microwave/ millimeter-wave bands employing an optical frequency quadrupling scheme

Abstract: To the best of our knowledge, a novel photonic architecture to generate vector signals at microwave/millimeter-wave bands employing an optical frequency quadrupling technique based on an external dual-parallel modulator is proposed for the first time. A 312.5 MSym/s quadruple phase-shift keying signal at 25 GHz is experimentally demonstrated using properly precoding driving signal at 6.25 GHz, and optical power penalty is negligible following 50 km single-mode fiber transmission.

RF MEMS High-Impedance Tuneable Metamaterials for Millimeter-Wave Beam Steering

Abstract: This paper presents the design, fabrication and evaluation of RF MEMS analog tuneable metamaterial high-impedance surfaces (HIS). These miniaturized structures are designed for W-band beam steering applications and are intended to replace a large multi-component subsystem by a single chip. Furthermore, the MEMS tuneable microwave metamaterials of this paper present a new class of microsystems interacting with microwaves, by uniquely combining the functionality of the microwave structures with the tuning MEMS actuators in one and the same distributed surface elements. A high-impedance surface array with 200 × 52 elements and a pitch of 350 m has been successfully fabricated and evaluated. The device features monocrystalline silicon membranes which are transfer-bonded on a multi-wafer silicon-glass substrate. The measured pull-in voltage is 15.9 V. Microwave measurements from 70 GHz to 114 GHz confirm the frequency selective nature of the surface. The fabricated devices showed a resonance frequency of 111.3 GHz to 111.8 GHz with losses ranging from -18 dB to -23 dB at the resonance and from -5 dB to -7 dB outside the resonance, which is worse than theoretically predicted but mainly attributed to imperfections in the design and fabrication of the first prototypes.

Very Broadband Extended Hemispherical Lenses: Role of Matching Layers for Bandwidth Enlargement

Abstract: The design and optimization of very broadband integrated lens antennas (ILAs) constitutes one of the future trends in lens antenna field. To this end we investigate numerically the radiation performance of millimeter wave ILAs coated with multiple anti reflection layers. We propose lens structures of moderate size (four wavelengths in diameter at the center frequency) and made from a dense dielectric material (ceramic). They are illuminated by two kinds of on-axis primary sources, namely a dielectric-loaded metallic waveguide and a patch antenna. This enables to assess the role of the lens illumination law on the performance of broadband ILAs. In particular, we demonstrate that ILAs coated with three stacked quarter wavelength matching layers exhibit a very broadband promising features. First their radiation characteristics remain very stable over a large frequency band: a 36% relative bandwidth is achieved using dielectric-loaded waveguide feeds. Secondly very high values of aperture efficiencies (beyond 91% over a 21% bandwidth) are obtained using printed feeds. The truncation effects of the ground plane and substrate of planar feeds upon the beam characteristics are also studied. We conclude that they must be taken into account at the very first stages of the design process of ILAs.

Broad band RF module of millimeter wave radar network for airport FOD detection system

Abstract: Foreign Objects and Debris (FODs) must be removed from runways. With the necessity of automatic continuous survey, we are investigating a new FOD detection system based on a millimeter wave radar network. This paper describes the concept of this FOD detection system and the Radio Frequency (RF) module for this application. In order to minimize cost and size, we installed a broadband FMCW radar using commercial Millimeter wave Monolithic ICs (MMICs) to improve range resolution, with a performance of a 5 GHz bandwidth at the 76 GHz band. We also present the results of practical tests and field tests at Sendai airport using 500 MHz FM deviation. The results indicated that it was sufficient to detect −20 dBsm FODs using low power MMW radar.

Millimeter-Wave UWB Signal Generation Via Frequency Up-Conversion Using Fiber Optical Parametric Amplifier

Abstract: We propose and demonstrate a novel approach to generate millimeter-wave (MMW) ultra-wideband (UWB) signal via frequency up-conversion using fiber optical parametric amplifier (OPA). The baseband UWB signal is amplified by a high-repetition-rate pulsed pump and generates many sidebands separated by the modulation frequency of the pump. By selecting two or three of the sidebands and beating in the photodetector, we can obtain an up-converted signal in the MMW band. In our experiment, we have successfully demonstrated UWB signal up-conversion from 3 to ~ 19 GHz with 18-dB optical gain using fiber OPA.

State-of-the-art of high power gyro-devices and free electron masers. Update 2008

Abstract: Gyrotron oscillators (gyromonotrons) are mainly used as high power millimeter wave sources for electron cyclotron resonance heating (ECRH), electron cyclotron current drive (ECCD), stability control and diagnostics of magnetically confined plasmas for generation of energy by controlled thermonuclear fusion. The maximum pulse length of commercially available 140 GHz, megawatt-class gyrotrons employing synthetic diamond output windows is 30 minutes (CPI and European FZK-CRPP-CEA-TED collaboration). The world record parameters of the European megawatt-class 140 GHz gyrotron are: 0.92 MW output power at 30 min. pulse duration, 97.5% Gaussian mode purity and 44% efficiency, employing a single-stage depressed collector for energy recovery. A maximum output power of 1.2 MW in 4.1 s pulses was generated with the JAEA-TOSHIBA 110 GHz gyrotron. The Japan 170 GHz ITER gyrotron holds the energy world record of 2.88 GJ (0.8 MW, 60 min.) and the efficiency record of 55% at 1 MW, 800 s for tubes with an output power of more than 0.5 MW. The Russian 170 GHz ITER gyrotron achieved 0.83 MW with a pulse duration of almost 203 s. Russian gyrotrons for plasma diagnostics or spectroscopy applications deliver Pout = 40 kW with τ = 40 μs at frequencies up to 650 GHz (η > 4%), P out = 1.5 kW at 1 THz (η = 2.2%), and P out = 0.5 kW at 1.3 THz (η = 0.7%). Gyrotron oscillators have also been successfully used in materials processing. Such technological applications require gyrotrons with the following parameters: f > 24 GHz , Pout = 4-50 kW, CW, η > 30%. This paper gives an update of the experimental achievements related to the development of high power gyrotron oscillators for long pulse or CW operation and pulsed gyrotrons for plasma diagnostics. In addition, this work gives a short overview of the present development status of coaxial-cavity multi-megawatt gyrotrons, gyrotrons for technological and spectroscopy applications, relativistic gyrotrons, quasi-optical gyrotrons, fast-and slow-wave cyclotron autoresonance masers (CARMs), gyroklystrons, gyro-TWT amplifiers, gyrotwystron amplifiers, gyro-BWO's, gyropeniotrons, magnicons, gyroharmonic converters, free electron masers (FEMs) and of vacuum windows for such high-power mm-wave sources. The highest CW powers produced by gyroklystrons and FEMs are, respectively, 10 kW (94 GHz) and 36 W (15 GHz). The IR FEL at the Thomas Jefferson National Accelerator Facility in the USA obtained a record average power of 14.2 kW at a wavelength of 1.6 μm. The THz FEL (NOVEL) at the Budker Institute of Nuclear Physics in Russia obtained a maximum average power of 0.5 kW in the wavelength range 110-240 μm (2.73-1.25 THz).

Millimeter-wave time-division linear frequency modulation multiple-target detection colliding-proof radar for car

Abstract: The invention relates to the technical field of radio fix radars, in particular to a millimetre wave time-division linear frequency modulation multi-object detection automobile anti-collision radar. The radar of the invention adopts full phase parameter receiving/emitting benchmark signal and time-division and time-sequence asynchronous control to receive/emit a dual-purpose quasi-light integrated medium lens antenna array, and scans the objects possible to be collided on the warning road surfaces by DSP according to lane scanning wave beam; the road situation photographing combined with the vehicle speed and GPS data MCU to control time-division n-passage modulation frequency and waveform millimetre wave linear locking phase frequency modulation; emission is carried out sequentially by R/T2, a circulator, a wave beam switch and the antenna array; echo passes through the antenna array, the wave beam switch, the circulator, the R/T1, low noise high amplifier, subharmonic mixing, middle amplifier and a time-dividing circuit and multi-object signal corresponding matching filter wave and is processed and controlled by MCU at DSP; when a plurality of road barriers are encountered, the orientation, distance and relative speed are determined by DSP restriction virtual warning; three-dimensional images are displayed by a CRT; the closer the distance of the object is, the higher the resolution is; the object which is closest to the vehicle is recognised; sound and light alarm are carried out when the distance is less than safety distance; when the distance is near to the dangerous distance, the vehicle can intelligently avoid the barrier or reduce the speed or brake; the radar of the invention can make a choice according to the control reference road situation, the vehicle speed and the GPS data, thus obviously improving the driving safety of the vehicle.

Design and performance of a distributed aperture millimeter-wave imaging system using optical upconversion

Abstract: Passive imaging using millimeter waves (mmWs) has many advantages and applications in the defense and security markets. All terrestrial bodies emit mmW radiation and these wavelengths are able to penetrate smoke, blowing dust or sand, fog/clouds/marine layers, and even clothing. One primary obstacle to imaging in this spectrum is that longer wavelengths require larger apertures to achieve the resolutions typically desired in surveillance applications. As a result, lens-based focal plane systems tend to require large aperture optics, which severely limit the minimum achievable volume and weight of such systems. To overcome this limitation, a distributed aperture detection scheme is used in which the effective aperture size can be increased without the associated volumetric increase in imager size. However, such systems typically require high frequency (~ 30 - 300 GHz) signal routing and down conversion as well as large correlator banks. Herein, we describe an alternate approach to distributed aperture mmW imaging using optical upconversion of the mmW signal onto an optical carrier. This conversion serves, in essence, to scale the mmW sparse aperture array signals onto a complementary optical array. The optical side bands are subsequently stripped from the optical carrier and optically recombined to provide a real-time snapshot of the mmW signal. In this paper, the design tradeoffs of resolution, bandwidth, number of elements, and field of view inherent in this type of system will be discussed. We also will present the performance of a 30 element distributed aperture proof of concept imaging system operating at 35 GHz.

Millimeter-wave time-division random code phase modulation multichannel colliding-proof radar for car

Abstract: The invention relates to the technical field of radio fix, in particular to a millimetre wave time-division random code phase modulation multi-passage automobile anti-collision radar. The radar of the invention is provided with a time-division and time-sequence asynchronous control to receive/emit signal, and a receive/emit a dual-purpose quasi-light integrated medium lens antenna array, and scans the objects possible to be collided on the warning road surfaces by DSP according to lane scanning wave beam; the road situation photographing, the vehicle speed sensing and satellite positioning GPS data MCU control time-division n-passage random code millimetre wave phase modulation; emission is carried out sequentially by upper frequency conversion, R/T3, frequency doubling and power amplification, R/T2, a circulator, a wave beam switch and the antenna array; echo passes through the antenna array, the wave beam switch, the circulator, the R/T1, low noise high amplifier, subharmonic mixing, middle amplifier and extracts the multi-passage signal DSP which is processed and controlled by MCU; the driving of multi-automobile of adjacent lanes is not disturbed by each other and can be completed simultaneously; the high-performance environment electromagnetic compatible EMC is provided; when a plurality of road barriers are encountered, the orientation, distance and relative speed are determined by DSP restriction virtual warning; three-dimensional panoramic images are displayed by a CRT; the closer the distance of the object is, the higher the resolution is; the object which is closest to the vehicle is recognized; sound and light alarm are carried out when the distance is less than safety distance; when the distance is near to the dangerous distance, the vehicle can intelligently avoid the barrier or reduce the speed or brake; the radar of the invention can make a choice according to the control reference road situation, the vehicle speed and the GPS data.

A 60 GHz Six-Port Distance Measurement System With Sub-Millimeter Accuracy

Abstract: A new compact six-port millimeter-wave distance measurement system is presented. The radar operates at the single frequency of 60 GHz and makes use of both the magnitude and phase of the measured free-space reflection coefficient to overcome the ambiguity of phase. The principle of operation, the system and experimental results are described in this letter.

Parametric Simulation and Optimization of Cold-test Properties for a 220 GHz Broadband Folded Waveguide Traveling-wave Tube

Abstract: Characterized with full-metal structure, high output power and broad bandwidth, microfabricated folded waveguide is considered as a robust slow-wave structure for millimeter wave traveling-wave tubes. In this paper, cold-test (without considering the real electron beam) properties were studied and optimized by 3D simulation on slow-wave structure, for designing a 220 GHz folded waveguide traveling-wave tube. The parametric analysis on cold-test properties, i.e., phase velocity, beam-wave interaction impedance and cold circuit attenuation, were conducted in half-period circuit with high frequency structure simulator, assisted by analytical model and equivalent circuit model. Through detailed parametric analyses, interference between specified structural parameters is found on determining beam-wave interaction impedance. A discretized matrix optimization for interaction impedance was effectively carried out to overcome the interference. A range of structural parameters with optimized interaction impedance distributions were obtained. Based on the optimized results, a broadband folded waveguide with cold pass-band of about 80 GHz, flat phase velocity dispersion and fairly high interaction impedance was designed for a 220 GHz central frequency traveling-wave tube. A three-dB bandwidth of 20.5 GHz and a maximum gain of 21.2 dB were predicted by small signal analysis for a 28 mm-long lossy circuit.

Millimeter-wave radio-over-fiber system based on two-step heterodyne technique.

Abstract: We theoretically demonstrate an improved two-step-heterodyne-based, millimeter-wave, radio-over-fiber system. With the millimeter-wave mixer and a fiber Bragg grating located in the base station, two-step heterodyne is achieved. The proposed scheme has the merit of good system performance and high suppression of unwanted frequency tones, which is verified by numerical simulations.

Substrate integrated waveguide six-port broadband front-end circuit for millimeter-wave radio and radar systems

Abstract: A novel multi-purpose integrated planar six-port front-end circuit combining both substrate integrated waveguide (SIW) technology and integrated loads is presented and demonstrated. The use of SIW technology allows a very compact circuit and very low radiation loss at millimeter frequencies. An integrated load is used to simplify the fabrication process and also reduce dimensions and cost. To validate the proposed concept, an integrated broadband six-port front-end circuit prototype was fabricated and measured. Simulation and measurement results show that the proposed six-port circuit can easily operate at 24 GHz for radar systems and also over 23–29 GHz for broadband millimetre-wave radio services.

Parametric Simulation and Optimization of Cold-test Properties for a 220 GHz Broadband Folded Waveguide Traveling-wave Tube

Abstract: Characterized with full-metal structure, high output power and broad bandwidth, microfabricated folded waveguide is considered as a robust slow-wave structure for millimeter wave traveling-wave tubes. In this paper, cold-test (without considering the real electron beam) properties were studied and optimized by 3D simulation on slow-wave structure, for designing a 220 GHz folded waveguide traveling-wave tube. The parametric analysis on cold-test properties, i.e., phase velocity, beam-wave interaction impedance and cold circuit attenuation, were conducted in half-period circuit with high frequency structure simulator, assisted by analytical model and equivalent circuit model. Through detailed parametric analyses, interference between specified structural parameters is found on determining beam-wave interaction impedance. A discretized matrix optimization for interaction impedance was effectively carried out to overcome the interference. A range of structural parameters with optimized interaction impedance distributions were obtained. Based on the optimized results, a broadband folded waveguide with cold pass-band of about 80 GHz, flat phase velocity dispersion and fairly high interaction impedance was designed for a 220 GHz central frequency traveling-wave tube. A three-dB bandwidth of 20.5 GHz and a maximum gain of 21.2 dB were predicted by small signal analysis for a 28 mm-long lossy circuit.

A New Wireless Displacement Sensor Based on Reverse Design of Microwave and Millimeter-Wave Antenna Array

Abstract: This paper introduces for the first time a new low-cost, nondestructive sensor to remotely monitor structural displacements (patent pending). The sensor consists of a two-element antenna array, operating at microwave or millimeter wave frequencies, remotely interrogated by a reader. The elements are stuck on the two sides of a crack to be monitored, no matter how large the crack is. The operating principle is based on the dependence of the array radiation characteristics on the element distance normalized to the wavelength. A combination of electromagnetic (EM) interferometry and Radio Frequency IDentification (RFID) technology allows the displacement of the antennas with respect to a reference configuration to be remotely determined. It is demonstrated that null measurements of the radiation pattern at microwave frequencies allow structural displacements to be predicted with uncertainties of the order of millimeters. The sensor accuracy is directly related to the wavelength of the radiated EM field.

Synthesis of Millimeter-Wave Power Spectra Using Time-Multiplexed Optical Pulse Shaping

Abstract: Millimeter-wave (MMW) electrical power spectra are flexibly synthesized by integrating fast wavelength switching, optical frequency comb generation, spectral line-by-line pulse shaping, and optical-to-electrical conversion. Control over generated RF power spectra is exercised through the choice both of the optical parent waveforms and of the wavelength switching patterns. Discrete or comb-like MMW power spectra are generated using periodic wavelength switching, while nearly continuous MMW spectra can be obtained when wavelengths are switched according to a pseudorandom bit stream.

Apparatus for managing frequency use

Abstract: A device includes a plurality of integrated circuits (ICs). An IC includes a millimeter wave (MMW) transceiver and a controller. The controller is operably coupled to the MMW transceiver and to: identify one or more other devices that have an intra-device MMW communication coverage area that overlaps with the intra-device MMW communication coverage area of the device. The controller also determines a first frequency range for use by the one or more other devices and the device for controlled radiation pattern intra-device MMW communications. The controller also coordinates allocation of a frequency use pattern to the one or more other devices and to the device for use for non-controlled radiation pattern intra-device MMW communications.

A 24/60GHz dual-band millimeter-wave on-chip monopole antenna fabricated with a 0.13-μm CMOS technology

Abstract: A 24 / 60GHz dual-band millimeter-wave on-chip antenna fabricated in TSMC 0.13-μm CMOS process is presented here. We design the feeding network by using the coplanar waveguide (CPW) structure. For the dual-band design, there are two major current paths to radiate. To avoid the harmonic frequency band of the low frequency-band, we add two strips to couple the harmonic frequency of the low frequency-band. Besides, the two strips let the higher frequency-band performance better. At this work, the simulator is based 3-D full-wave EM solver, Ansoft HFSS. The on-chip antenna size is 0.76 X 1.045 mm2. The bandwidth of the lower band and higher is about 180MHz and 700MHz, respectively. The simulated gain is about −9dB for 24GHz and about 1dB for 60GHz

Device and method for generating 8 times frequency optical millimeter waves by utilizing lithium niobate modulator

Abstract: The invention discloses a device and a method for generating 8 times frequency optical millimeter waves by utilizing a lithium niobate modulator, mainly applicable to the generation of optical millimeter waves in the radio over fiber (RoF) network. The method as shown in the attached figure comprises the following steps: high-level sideband is generated on the deep modulated nonlinearity by utilizing lithium niobate nested Mach-Zehnder modulator; the sideband interference of 4n+1, 4n+2, and 4n+3 stages can be countervailed under proper voltage offset; the optical wave is inhibited by a filter; as the sideband amplitude of the eighth and higher stages is less than that of the fourth stage sideband, the optical millimeter wave signals are mainly composed of the +/- four stage sideband of which the frequency interval equals to eight times of the local oscillator frequency, and the electric millimeter wave frequency generated by the beat frequency of a photoelectric detector is eight times of the local oscillator frequency of radio frequency. The method has the advantages of low needed local oscillator frequency and modulator response frequency, no amplitude fading of the generated optical millimeter waves when transmitting in the optical fiber, narrow width of the radio frequency signal wires generated during photoelectric transformation and the like, thus having good application prospect.

Robust Microstrip-to-Waveguide Transitions for Millimeter-Wave Radar Sensor Applications

Abstract: Two robust millimeter-wave microstrip-to-waveguide transitions are proposed in this paper. The central operating frequency is 77 GHz, for collision-avoidance radar applications. The microstrip line has been first transformed into an air-filled rectangular waveguide whose height is equal to the substrate thickness. Then, a conventional multisection lambda/4 transformer has been used in the first transition, and a patch antenna in the second transition, to transform to the feeding WR12 waveguide. Experimental results for the first transition show an insertion loss less than 2 dB and a return loss better than 15 dB in a bandwidth of 3 GHz for the back-to-back transition.

Image capturing apparatus

Abstract: PROBLEM TO BE SOLVED: To provide an image capturing apparatus having a shake correcting function to move a solid-state imaging device, wherein signal transmission is performed with a millimeter wave without depending on electric wiring between an imaging substrate on which the solid-state imaging device is mounted and other substrate. SOLUTION: A semiconductor chip 103 constituting a first communication device is mounted on a main substrate 602A for performing the signal transmission with the imaging substrate 502A on which the solid-state imaging device 505 is mounted, and a semiconductor 203 constituting a second communication device is mounted on the imaging substrate 502A. A shake correction driving part 510 is arranged around the imaging substrate 502A. An image processing engine 605 in which a control signal generation part and an image processing unit are housed is also mounted on the main substrate 602A. The semiconductor chips 103 and 203 convert a base band signal into the millimeter wave in a millimeter wave signal generation part, and are coupled with a millimeter wave signal transmission line 9 through antennas 136 and 236. The millimeter wave transmitted through the millimeter wave signal transmission line 9 is received through the antennas 136 and 236, and restored to the base band signal in a base band signal generation part. COPYRIGHT: (C)2011,JPO&INPIT

Development of 77 GHz millimeter wave passive imaging camera

Abstract: 77 GHz millimeter wave passive imaging camera for the purpose of security is developed. In order to detect concealed objects in clothes without hindrance to flow of people at airport security checks, video rate imaging is realized using one-dimensional imaging sensor array of 25 elements and a flapping reflector. As receiving antennas, novel antipodal Fermi antenna (APFA) having required characteristics for passive imaging such as broadband to obtain enough power, axially symmetric directivity with 10dB beam width of 35 degrees to obtain optimum coupling with dielectric lens, narrow width geometry for high spatial resolution of imaging is used. High spatial resolution of 20 mm (width of finger) is obtained by using developed passive imaging camera.

Millimeter-Wave Lumped Element Superconducting Bandpass Filters for Multi-Color Imaging

Abstract: The opacity due to water vapor in the Earth's atmosphere obscures portions of the sub-THz spectrum (mm/sub-mm wavelengths) to ground based astronomical observation. For maximum sensitivity, instruments operating at these wavelengths must be designed to have spectral responses that match the available windows in the atmospheric transmission that occur in between the strong water absorption lines. Traditionally, the spectral response of mm/sub-mm instruments has been set using optical, metal-mesh bandpass filters [1]. An alternative method for defining the passbands, available when using superconducting detectors coupled with planar antennas, is to use on-chip, superconducting filters [2]. This paper presents the design and testing of superconducting, lumped element, on-chip bandpass filters (BPFs), placed inline with the microstrip connecting the antenna and the detector, covering the frequency range from 209-416 GHz. Four filters were designed with pass bands 209-274 GHz, 265-315 GHz, 335-361 GHz and 397-416 GHz corresponding to the atmospheric transmission windows. Fourier transform spectroscopy was used to verify that the spectral response of the BPFs is well predicted by the computer simulations. Two-color operation of the pixels was demonstrated by connecting two detectors to a single broadband antenna through two BPFs. Scalability of the design to multiple (four) colors is discussed.