Showing papers on "Extremely high frequency published in 2014"

Millimeter Wave Channel Modeling and Cellular Capacity Evaluation

Abstract: With the severe spectrum shortage in conventional cellular bands, millimeter wave (mmW) frequencies between 30 and 300 GHz have been attracting growing attention as a possible candidate for next-generation micro- and picocellular wireless networks. The mmW bands offer orders of magnitude greater spectrum than current cellular allocations and enable very high-dimensional antenna arrays for further gains via beamforming and spatial multiplexing. This paper uses recent real-world measurements at 28 and 73 GHz in New York, NY, USA, to derive detailed spatial statistical models of the channels and uses these models to provide a realistic assessment of mmW micro- and picocellular networks in a dense urban deployment. Statistical models are derived for key channel parameters, including the path loss, number of spatial clusters, angular dispersion, and outage. It is found that, even in highly non-line-of-sight environments, strong signals can be detected 100-200 m from potential cell sites, potentially with multiple clusters to support spatial multiplexing. Moreover, a system simulation based on the models predicts that mmW systems can offer an order of magnitude increase in capacity over current state-of-the-art 4G cellular networks with no increase in cell density from current urban deployments.

Millimeter wave transmission device, millimeter wave transmission method, and millimeter wave transmission system

Abstract: The device includes: a signal generating unit generating a millimeter wave signal by signal processing of an input signal; a coupling circuit transmitting an electromagnetic wave from the millimeter wave signal generated by the signal generating unit to one end of a circuit board; a coupling circuit receiving the electromagnetic wave from the millimeter wave signal from the other end of the circuit board; and a signal generating unit that generates an output signal by signal processing of the millimeter wave signal from the electromagnetic wave received by the coupling circuit. Preferably, the circuit board is constituted by a dielectric material whose the dielectric loss tangent is relatively large, and a transmission line functioning as a millimeter wave transmission path is constituted within this circuit board. With this construction, extremely high-speed signals can be transmitted through a circuit board having a prescribed dielectric constant representing a large loss.

Microwave Photonic Integrated Circuits for Millimeter-Wave Wireless Communications

Abstract: This paper describes the advantages that the introduction of photonic integration technologies can bring to the development of photonic-enabled wireless communications systems operating in the millimeter wave frequency range. We present two approaches for the development of dual wavelength sources for heterodyne-based millimeter wave generation realized using active/passive photonic integration technology. One approach integrates monolithically two distributed feedback semiconductor lasers along with semiconductor optical amplifiers, wavelength combiners, electro-optic modulators and broad bandwidth photodiodes. The other uses a generic photonic integration platform, developing narrow linewidth dual wavelength lasers based on arrayed waveguide gratings. Moreover, data transmission over a wireless link at a carrier wave frequency above 100 GHz is presented, in which the two lasers are free-running, and the modulation is directly applied to the single photonic chip without the requirement of any additional component.

Experimental Demonstration of Photonic Millimeter-Wave System for High Capacity Point-to-Point Wireless Communications

Abstract: We present experimental results of 10 Gb/s wireless communications over a distance of 520 meters in the W-band. The transmitter makes use of photonic upconversion with a high bandwidth photodiode to allow for minimum hardware at the antenna. We present results with two receiver configurations. The first uses all electronic methods with a balanced Schottky diode mixer for downconversion, and the second uses photonics to limit the hardware at the receive antenna by photonically generating the local oscillator drive signal and transporting the intermediate frequency signal over a microwave photonic link.

Triple transit region photodiodes (TTR-PDs) providing high millimeter wave output power

Abstract: We report on a novel triple transit region (TTR) layer structure for 1.55 μm waveguide photodiodes (PDs) providing high output power in the millimeter wave (mmW) regime. Basically, the TTR-PD layer structure consists of three transit layers, in which electrons drift at saturation velocity or even at overshoot velocity. Sufficiently strong electric fields (>3000 V/cm) are achieved in all three transit layers even in the undepleted absorber layer and even at very high optical input power levels. This is achieved by incorporating three 10 nm thick p-doped electric field clamp layers. Numerical simulations using the drift-diffusion model (DDM) indicate that for optical intensities up to ~500 kW/cm2, no saturation effects occur, i.e. the electric field exceeds the critical electric field in all three transit layers. This fact in conjunction with a high-frequency double-mushroom cross-section of the waveguide TTR-PD ensures high output power levels at mmW frequencies. Fabricated 1.55 µm InGaAs(P)/InP waveguide TTR-PDs exhibit output power levels exceeding 0 dBm (1 mW) and a return loss (RL) up to ~24 dB. Broadband operation with a 3 dB bandwidth beyond 110 GHz is achieved.

Photonic Beamsteering of a Millimeter-Wave Array With 10-Gb/s Data Transmission

Abstract: We present experimental results of 10-Gb/s W-band wireless transmission using a four element linear array. The 10-Gb/s transmission is shown when photonically steered to 0° and ± 35° from antenna boresight. In this letter, photonic techniques are used for signal generation, distribution, and time delay. Photonic true-time delay is shown to allow for steering of broadband millimeter-wave signals with no noticeable beam squint across frequency. High power, high frequency photodiodes are used for optical-to-electrical conversion to directly radiate from the array without power amplifiers.

Coherent Filterless Wideband Microwave/Millimeter-Wave Channelizer Based on Broadband Parametric Mixers

Abstract: An essential capability in many applications, ranging from commercial, surveillance and defense, is to analyze the spectral content of intercepted microwave and millimeter-wave signals over a very wide bandwidth in real-time and with high resolution. A range of photonic schemes have been introduced for the real-time processing of wideband signals to overcome limitations of current conventional electronic frequency measurement approaches. Here, a novel microwave/millimeter-wave channelizer is presented based on a RF photonic front-end employing parametric wavelength multicasting and comb generation. This new technology enables a contiguous bank of channelized coherent I/Q IF signals covering extremely wide RF instantaneous bandwidth. High channel counts and wide RF instantaneous bandwidth are enabled by use of parametrically generated frequency-locked optical combs spanning >4 THz. Full field analysis capabilities of the coherent detection system are demonstrated by frequency domain analysis of 18 contiguous 1.2 GHz IF channels covering 15.5 GHz to 37.1 GHz input frequency range, and time and spectral domain analysis of a 75 GHz harmonically generated input signal. Sensitivity and dynamic range of the system are analyzed and discussed.

Evaluation of Empirical Ray-Tracing Model for an Urban Outdoor Scenario at 73 GHz E-Band

Abstract: In the summer of 2013, a wideband propagation measurement campaign using rotating directional antennas at 73 GHz was conducted at the New York University (NYU) campus, in order to collect extensive field measurements for use in a millimeter wave (mmWave) E-band statistical channel model. While the measurement campaign provided over 50 Gigabytes of wideband power delay profiles and angular responses [1], [2], the time and labor intensive measurements were based on only 5 transmitter (Tx) locations and 27 receiver (Rx) locations, making up a total of 74 Tx-Rx link combinations. To help generalize the measurements for immediate model development and eventual site planning, this paper presents an empirical ray-tracing model, with the goal of finding a suitable approach such that ray-tracing (RT) can fill in the gaps of the measurements. Here, we use the measured data to investigate the prediction capability of an empirical RT model, in which the 3D model of New York City (including the building structures and interaction losses) are greatly simplified. The comparison between the measured and predicted results show good accuracy is obtained when a simplified RT model is used, suggesting that fast and simple ray tracers will be able to correctly predict the propagation characteristics at mmWave bands.

Multi-Chroic Dual-Polarization Bolometric Detectors for Studies of the Cosmic Microwave Background

Abstract: We are developing multi-chroic antenna-coupled Transition Edge Sensor (TES) bolometer detectors for Cosmic Microwave Background (CMB) polarimetry. Multi-chroic detectors increase focal plane area efficiency, and thus the mapping speed per focal plane area, and provide greater discrimination against polarized galactic foregrounds with no increase in weight or cryogenic cost. In each pixel, a silicon lens-coupled dual-polarized sinuous antenna collects photons over a two-octave frequency band. The antenna couples the broadband millimeter wave signal into microstrip transmission lines, and on-chip filter banks split the broadband signal into multiple frequency bands. Separate TES bolometers detect the power in each frequency band and linear polarization state. We will describe the design and performance of these devices and present optical data taken. Our measurements of dual-polarization pixels in multiple frequency bands show beams with percent-level ellipticity, and percent-level cross-polarization leakage. We will also describe the development of large arrays of these multi-chroic pixels. Finally, we will describe kilo-pixel arrays of these detectors planned for the future CMB experiments that will achieve unprecedented mapping speed.

Millimeter Wave Detection via Autler-Townes Splitting in Rubidium Rydberg Atoms

Abstract: In this paper we demonstrate the detection of millimeter waves via Autler-Townes splitting in 85Rb Rydberg atoms. This method may provide an independent, atom-based, SI-traceable method for measuring mm-wave electric fields, which addresses a gap in current calibration techniques in the mm-wave regime. The electric- field amplitude within a rubidium vapor cell in the WR-10 waveguide band is measured for frequencies of 93 GHz, and 104 GHz. Relevant aspects of Autler-Townes splitting originating from a four-level electromagnetically induced transparency scheme are discussed. We measure the E-field generated by an open-ended waveguide using this technique. Experimental results are compared to a full-wave finite element simulation.

Invited Article: Dielectric material characterization techniques and designs of high-Q resonators for applications from micro to millimeter-waves frequencies applicable at room and cryogenic temperatures

Abstract: Dielectric resonators are key elements in many applications in micro to millimeter wave circuits, including ultra-narrow band filters and frequency-determining components for precision frequency synthesis. Distributed-layered and bulk low-loss crystalline and polycrystalline dielectric structures have become very important for building these devices. Proper design requires careful electromagnetic characterization of low-loss material properties. This includes exact simulation with precision numerical software and precise measurements of resonant modes. For example, we have developed the Whispering Gallery mode technique for microwave applications, which has now become the standard for characterizing low-loss structures. This paper will give some of the most common characterization techniques used in the micro to millimeter wave regime at room and cryogenic temperatures for designing high-Q dielectric loaded cavities.

Dual frequency laser with two continuously and widely tunable frequencies for optical referencing of GHz to THz beatnotes

Abstract: A dual-frequency 1.55 µm laser for CW low noise microwave, millimeter and sub millimeter wave synthesis is demonstrated, where frequency stabilization is possible on each wavelength independently. The solid state Er:Yb laser output power is 7 mW. The amplitude noise is −150 dBc/Hz at 1 MHz offset frequency. In free running regime, the frequency noise is 3.105/f Hz/sqrt(Hz) (800 Hz on a 1µs timescale), better than commercial fibered or semi-conductor sources at this wavelength.

Directional Beamforming for Millimeter-Wave MIMO Systems

Abstract: The focus of this paper is on beamforming in a millimeter-wave (mmW) multi-input multi-output (MIMO) set-up that has gained increasing traction in meeting the high data-rate requirements of next- generation wireless systems. For a given MIMO channel matrix, the optimality of beamforming with the dominant right-singular vector (RSV) at the transmit end and with the matched filter to the RSV at the receive end has been well-understood. When the channel matrix can be accurately captured by a physical (geometric) scattering model across multiple clusters/paths as is the case in mmW MIMO systems, we provide a physical interpretation for this optimal structure: beam steering across the different paths with appropriate power allocation and phase compensation. While such an explicit physical interpretation has not been provided hitherto, practical implementation of such a structure in a mmW system is fraught with considerable difficulties (complexity as well as cost) as it requires the use of per-antenna gain and phase control. This paper characterizes the loss in received SNR with an alternate low-complexity beamforming solution that needs only per-antenna phase control and corresponds to steering the beam to the dominant path at the transmit and receive ends. While the loss in received SNR can be arbitrarily large (theoretically), this loss is minimal in a large fraction of the channel realizations reinforcing the utility of directional beamforming as a good candidate solution for mmW MIMO systems.

Millimeter-Wave Generation in an Optoelectronic Oscillator Using an Ultrahigh Finesse Etalon as a Photonic Filter

Abstract: A Fabry-Perot etalon with a finesse of 100 000 is used as a photonic filter in a single loop optoelectronic oscillator. The etalon provides narrow bandwidth microwave filtering at harmonics of its 1.5 GHz free spectral range for oscillation in the range of 6 to 60 GHz. Fiber delays as long as 2 km are added to the loop with no spurious modes visible above the noise floor. The environmental stability of the etalon makes it suitable as a secondary reference for feedback to the optical frequency which contributes to the reduction of phase noise and long term frequency drift.

Miniature active microwave and millimeter wave I/Q variable phase reversal quadrature filter

Abstract: The invention discloses a miniature active microwave and millimeter wave I/Q variable phase reversal quadrature filter. The filter comprises a single-pole double-throw switch chip WKD102010040, a low-noise amplifier chip WFD022036-L12, a 50-ohm resistance input/output interface attached to the surface, a parallel resonance unit module of a strip line structure, and a broadside coupling strip line of a dual-spiral structure. The above-mentioned structures are all obtained through the multi-layer low-temperature cofired ceramics technology (LTCC technology). The filter has the advantages of being variable, capable of achieving phase reversal quadrature, low in insertion loss, easy to adjust, light in weight, small in size, high in reliability, good in electrical performance, high in temperature stability, low in cost, capable of being produced on a large scale and the like, and is suitable for occasions with strict requirements of communication, satellite communication and the like in corresponding millimeter wave frequency bands for the size, electrical performance, temperature stability and reliability, and suitable for corresponding systems.

Distribution of high-stability 100.04 GHz millimeter wave signal over 60 km optical fiber with fast phase-error-correcting capability.

Abstract: We demonstrate a phase-stabilized remote distribution of 100.04 GHz millimeter wave signal over 60 km optical fiber. The phase error of the remote millimeter wave signal induced by fiber transmission delay variations is detected by dual-heterodyne phase error transfer and corrected with a feedback system based on a fast response acousto-optic frequency shifter. The phase noise within the bandwidth of 300 Hz is effectively suppressed; thus, the fast transmission delay variations can be compensated. The residual phase noise of the remote 100.04 GHz signal reaches −56 dBc/Hz at 1 Hz frequency offset from the carrier, and long-term stability of 1.6×10−16 at 1000 s averaging time is achieved. The fast phase-noise-correcting capability is evaluated by vibrating part of the transmission fiber link.

Investigation of a photodefinable glass substrate for millimeter-wave radios on package

Abstract: Photodefinable glass has been investigated for applications at mm-wave frequencies. Test structures including through-glass vias, transmission lines and microstrip patch antennas have been fabricated and fully characterized up to 67 GHz. Good correlation was obtained between simulation and measurements. The antenna exhibited return loss better than 10 dB in the frequency band of interest. Via transition losses were less than 0.15 dB/via and the transmission line insertion loss was ~ 3.3 dB/cm at 60 GHz.

Optical Measurements of SuperSpec: A Millimeter-Wave On-Chip Spectrometer

Abstract: SuperSpec is a novel on-chip spectrometer we are developing for (sub)millimeter wavelength astronomy. Our approach utilizes a filterbank of moderate resolution (R∼500) channels, coupled to lumped element kinetic inductance detectors (KIDs), all integrated onto a single silicon chip. The channels are half-wave resonators formed by lithographically depositing segments of superconducting transmission line, and the KIDs are titanium nitride resonators. Here we present optical measurements of a first generation prototype, operating in the 180–280 GHz frequency range. We have used a coherent source to measure the spectral profiles of 17 channels, which achieve linewidths corresponding to quality factors as high as Q__(filt)=700, consistent with the designed values plus additional dissipation characterized by Q_i≈1440. We have also used a Fourier Transform Spectrometer to characterize the spectral purity of all 72 channels on the chip, and measure typical out of band responses ∼30 dB below the peak response.

On-wafer magnetically tunable millimeter wave notch filter using M-phase Ba hexagonal ferrite/Pt thin films on Si

Abstract: A prototype of a fully integrated on-wafer, magnetically tunable band-stop filter operating at millimeter wave frequencies is demonstrated on a Si substrate. In contrast to earlier studies, the filter uses a very thin barium hexagonal ferrite film incorporated into the dielectric layer of a microstrip transmission line to filter the signal. The zero-field operational frequency is about 34 GHz, increasing linearly with the strength of a static, perpendicularly applied magnetic field at a rate of about 2.7 GHz/kOe. Experimentally, high signal attenuation (33–67 dB/cm) at the resonance frequency and insertion losses as low as 4.5 dB were simultaneously observed, while the 3 dB device bandwidths were generally below 1 GHz. Our calculations are in quantitative agreement with the experimental results. We also find an important result that the thickness and conductivity of the Pt ground plane plays a key role in insertion losses, indicating directions for further improvements.

A dual polarization, broadband, millimeter-wave reflectarray using modified cross loop element

Abstract: A Ka-band reflectarray consisting of modified cross loop is investigated in this article for millimeter-wave broadband dual-polarization applications. It consists of 40 × 40 unit cells that covered an area of 200 × 200 mm2 and a multimode conical horn antenna which is connected to an orthomode transducer as the offset feed. Its unit cell is composed of a solid cross inside and a cross loop outside, which can lead to nearly 550° linear phase shift curve by varying its length. After this proposed structure has been analyzed and compared with the traditional wideband element (i.e., double cross loop), it is used in the reflectarray. An equivalent circuit model with an insightful field distribution is used to analyze their different behaviors when it resonated at the same operating frequency. For vertical and horizontal polarization modes, the peak gain are measured to be 34.3 and 33.5 dB, the aperture efficiency are 48.6% and 40.4% at the center frequency of 32 GHz, respectively. The 1.5 dB gain bandwidth are close to 18% and 15%, which is better than conventional millimeter-wave single-layer ones. This new reflectarray antenna is especially useful for millimeter-wave broadband dual-polarization applications. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:287–293, 2014

Millimeter-Wave Silicon-on-Glass Integrated Tapered Antenna

Abstract: This letter presents a millimeter-wave (mmW) high-efficiency tapered dielectric antenna, which is designed and fabricated on a new integrated technology platform called silicon-on-glass (SOG). The antenna is fabricated using photolithography and dry etching of the Si layer of the SOG wafer. The proposed antenna advantages include high efficiency, low-cost fabrication with high precision, and small size. Experimental results are presented to validate the new design concept, which is optimized for low sidelobe, high gain, and short length.

Low Loss, Wideband, and Compact CPW-Based Phase Shifter for Millimeter-Wave Applications

Abstract: This paper proposes a compact, low-loss, and low cost phase shifter for millimeter-wave phased array systems. The basic idea is to modify the propagation mode of a coplanar waveguide (CPW) by placing a high dielectric constant (40 <; e r <; 170) slab on top of it. The phase shift is varied by changing the air gap between the CPW line and the dielectric slab. A piezoelectric transducer has been used to control this air gap precisely. For fast but accurate modeling of the proposed phase shifter, two methods one based on spectral domain analysis and the other based on the conformal mapping have been developed and verified with full wave simulations and measurements. A prototype structure with the operational frequency range from 20 to 40 GHz is presented. The maximum phase shift obtained for the electrically controlled version at 40 GHz is 103 ° with loss variation of 0.2 dB. The total length is 2 mm.

Compact and Sensitive Millimetre Wave Detectors Based on Low Barrier Schottky Diodes on Impedance Matched Planar Antennas

Abstract: Compact and highly responsive millimeter wave planar Schottky detectors are proposed for uni-planar and low-cost fabrication. For optimum power transfer, the zero-bias Schottky diodes are impedance matched by the antenna design itself, with an established meander dipole and a new folded dipole type. In particular, up to 200GHz, the folded dipole exhibits a single responsivity peak, notably beneficial for communications. The realized detectors exhibit an outstanding system RF voltage responsivity of up to 16005mV/mW at 87.8GHz without lenses or pre amplification. In addition, an excellent NEP level is demonstrated by the detectors with 0.39pW/ $\sqrt {\text {Hz}}$ .

Wideband multibeam millimeter wave arrays

Abstract: Monolithic millimeter wave Butler matrix and Rotman lens array topologies built using surface micromachining are presented. By using wideband couplers and transmission lines, instantaneous bandwidths of 50 GHz and 100 GHz are achieved. Measurements, including radiation patterns in W band confirm both, their good performance, and overall operating bandwidth.

SU-8 2000 Millimeter Wave Material Characterization

Abstract: SU-8 2000 is an epoxy based photoresist widely used in the fabrication of MEMS for its thick film capability. SU-8 also holds promise as a low cost material for millimeter wave packaging and devices where thick films are required. This letter investigates the electrical material properties of SU-8 2000 at frequencies beyond 140 GHz. Characterization using microstrip ring and T resonators reveal a dielectric constant of 3.0 across the entire band with an approximate loss tangent of 0.04.

Electromagnetic Waves Absorbing Characteristics of Composite Material Containing Carbonyl Iron Particles

Abstract: Results of measurements of permeability, permittivity and radar absorption properties of composites on basis of carbonyl iron particles R-10 brand are presented in this paper. The calculations and experimental studies have shown that in the super high frequency (SHF) and extremely high frequency (EHF) ranges on the basis of two-layer structures with different content of carbonyl iron particles can create a radar absorbing coatings with a reflectivity of less than -10 dB over a wide bandwidth from 3.1 to 17.1 GHz and from 27 to 37 GHz. Absorbing properties of composites are saved in terahertz frequency range from 250 to 525 GHz.

Photonic generation of background-free millimeter-wave ultra-wideband pulses based on a single dual-drive Mach-Zehnder modulator

Abstract: We propose a novel photonic approach for generating a background-free millimeter-wave (MMW) ultra-wideband (UWB) signal based on a conventional dual-drive Mach-Zehnder modulator (DMZM). One arm of the DMZM is driven by a local oscillator (LO) signal. The LO power is optimized to realize optical carrier suppressed modulation. The other arm is fed by a rectangular signal. The MMW UWB pulses are generated by truncating the continuous wave LO signal into a pulsed one in a photodetector (PD). The generated MMW UWB signal is background-free by eliminating the baseband frequency components because the optical power launched to the PD keeps constant all the time. The proposed method is theoretically analyzed and experimentally verified. The generated MMW UWB signal centered at a frequency of 26 GHz meets the Federal Communications Commission spectral mask very well.

A microwave or millimeter wave RF part using pin grid array (PGA) and/or ball grid array (BGA) technologies

Abstract: The present invention relates to the technology used to design, integrate and package the radio frequency (RF) part of an antenna system, for use in communication, radar or sensor applications, consisting of components such as waveguide couplers, diplexers, filters, distribution networks, antennas, integrated circuit packages and the like. The invention makes use of pin grid arrays (PGA) and ball grid arrays (BGA) to realize the RF part, based on the principle of gap waveguides. Gap waveguides are formed in the gaps between conducting surfaces. Thereby flat multilayer RF parts can be realized, as well as completely integrated RF front-ends including the packaged MMICs and frequency converters. The PGA and BGA technologies have never before been applied to RF applications.