Integrated-optic ring resonators with two stacked layers of silicawaveguide on Si

A ring resonator with a radius of 1.5 mm is demonstrated using a stack structure consisting of two layers of GeO₂-doped silica waveguide with different refractive index differences (Δ). One is a high-Δ waveguide layer with a Δ of 2% for a small-radius ring and the other is a waveguide layer with a Δ of 0.75% for good fiber coupling. The waveguides and a flattened middle-cladding layer are stacked on a Si substrate. The ring resonator exhibited a wide free spectral range (FSR) of 21.6±0.1 GHz and a high finesse of 110±10     

Performance of single- and double-ring resonators using 3×3optical-fiber coupler

This paper investigates theoretically the transmission characteristics of single- and double-ring resonators using 3×3 optical-fiber couplers. Two configurations of a 3×3 coupler are considered: configuration A, with the three fibers centered at the vertices of an equilateral triangle, and configuration B, with their centers aligned in a straight line. It is found that a ring resonator using configuration A does not show any performance improvement over ring resonators using 2×2 couplers. On the other hand, a single-ring resonator using configuration B has a performance close to resonators using 2×2 couplers. It is also shown that a double-ring resonator using a 3×3 coupler exhibits resonance with a double peak, which may find application in the filtering of coherent frequency-shift keying (FSK) signals after optical amplification in an optical-fiber line repeater     

Wide-wavelength tunable lasers with 100 ghz fsr ring resonators

A widely tunable laser, consisting of a 100 GHz FSR triple-ring resonator and a semiconductor optical amplifier, is presented. The 100 GHz FSR ring resonator makes it possible to demonstrate 96 nm wavelength tuning with stable single-mode operation produced by a large threshold gain difference     

Integrated-optic implementation of a confocal scanning opticalmicroscope

A confocal scanning optical microscope implemented in an integrated-optic structure is demonstrated. The compact nature of the device proves to be more suitable for environments where mechanical shock can result in optical misalignment of discrete components. The device is implemented in a thin-film optical waveguide with optical fiber connections for light input and output. An objective lens and focusing beam splitter are incorporated into the waveguide structure to form the sensing head of the microscope. The fabrication of the device is discussed, and both intensity and differential contrast images are presented to demonstrate the device operation. The confocal imaging characteristics of the microscope are also demonstrated     

Beam focusing using 60 GHz Fabry-Perot resonators with uniform and non-uniform metal grids

A new structure of millimetre-wave focusing antennas is presented. It consists of a plane-parallel Fabry-Perot resonator comprising two uniform and non-uniform inductive metal meshes excited by a horn antenna. The beam focusing is performed with the non-uniform mirror, the geometry of which is chosen so that it behaves as a spherical equiphase surface with a desired radius of curvature. The resulting radiation patterns are Gaussian; their directivity is controlled by the curvature of the synthesised wavefront. This concept is successfully validated in the 60 GHz band.     

Propagation in wide tunnels at 2 GHz: a statistical analysis

This paper describes the main statistical characteristics of the propagation channel in a tunnel of large transverse dimensions, with the carrier frequency being near 2 GHz. Theoretical and experimental results on the fading distribution as well as those deduced from a wide-band analysis are presented     

A 900-MHz 1.5-V CMOS voltage-controlled oscillator using switched resonators with a wide tuning range

A 900-MHz fully integrated VCO was fabricated in a 0.18-/spl mu/m foundry CMOS process. Under 1.5 V power supply, this VCO can be tuned from 667 MHz to 1156 MHz which corresponds to a 53.6% tuning range. The VCO has nearly constant phase noise over the whole tuning frequency, credit to the switched resonators used in this VCO. The phase noise at a 600 kHz offset is -123.1 dBc/Hz at 1125 MHz center frequency and -124.2 dBc/Hz at 667 MHz center frequency.     

平板宽波导谐振腔耦合损失理论研究

计算了平板宽波导谐振腔中ＥＨ１１模的耦合损失，结果表明存在两种特定结构使耦合损失最小。     

Design of Subharmonic Mixers above 100 GHz

This paper presents the design and simulation of several fixed-tuned sub-harmonic mixers cover frequencies from 110 GH to 130 GHz, 215 GH to 235 GHz, 310 GH to 350 GHz, and 400 GH to 440 GHz. Among them, 120 GHz, 225 GHz, 330 GHz subharmonic mixers are designed with flip-chipped planar schottky diode mounted onto a suspended quartz-based substrate, the 225 GHz and 425 GHz subharmonic mixers are GaAs membrane integrated, and the 115 GHz subharmonic mixer has been fabricated and tested already.     

基于薄膜工艺的1 030 GHz混频器和750~1 100 GHz倍频器研制

基于南京电子器件研究所砷化镓工艺线,自主完成了750~1 100 GHz全频带三倍频器以及中心频率为1 030 GHz的低损耗二次谐波混频器的研制。为了提升模块的性能,将传统的场路结合的设计方法进行了扩展,引入器件的参数优化,并建立起两者互为反馈的关系,从而达到整个设计过程的闭环。研制出的单片电路厚度为3 μm,并通过梁氏引线支撑悬置于腔体结构中。测试结果表明宽带倍频器在790~1 100 GHz频率范围内输出功率为-23~-11 dBm。以上述倍频源作为射频信号对二次谐波混频器进行测试,在1 020~1 044 GHz频率范围内变频损耗优于17.5 dB,在1 030 GHz处测得的最小变频损耗为14.5 dB。     

An SIS mixer for 90–120 GHz with gain and wide bandwidth

An SIS mixer for the 3 mm wavelength band has been developed. It has sufficient RF bandwidth to allow double-sideband operation at an IE of 1.4 GHz. Available gain of around 3 dB has been measured, along with mixer temperatures of 20 to 40K (both double sideband). The junctions were fabricated using a lead-alloy technology (Pb?In?Au/oxide/-Pb?Bi). Coupling and tuning structures were integrated onto a quartz substrate along with the junctions. The measurements were made at physical temperatures around 3.1K, achieved with a closed-cycle refrigerator.     

Characteristics of double-groove guide for 100 GHz operation

There are two types of possible transmission modes in double-groove guides. They are:

1. modes with a concentration of energy in the groove regions (region A), and
2. modes with a concentration of energy in the region between the two grooves (region S).

Attention had been concentrated on the first type of modes[1]. This paper gives the theoretical and experimental work on the second type of modes.     

Analysis of a wide range of microwave resonators: t.l.m. methods

The solution of large m.i.c.-subassemblies presents a major problem to any numerical method. However, it would seem that the first step should involve a numerical routine of a very general nature for simple discontinuities in 3-dimensional structures. The letter describes how the t.l.m. method of numerical analysis in the form of a very general computer program fulfils this requirement.     

Integrated packaging of over 100 GHz bandwidthuni-traveling-carrier photodiodes

Hybrid packaging techniques, in which the device substrate is different from the package substrate, and wire bonding or solder interconnections are used, are inadequate for ultrahigh-speed (>100 GHz) wideband applications. By employing wafer-bonding techniques, an integrated packaging (IP) technology was developed, in which devices are fabricated directly on the package substrate, and the interconnections are made as a part of the device fabrication process. This IP process was used to fabricate uni-traveling-carrier photodiodes (UTC-PD's) integrated with millimeter-wave coplanar waveguides (CPW) on package compatible sapphire with high yield. The performance of wafer-bonded UTC-PD's with 3-dB bandwidth of 102 GHz was similar to that of conventional devices, and the CPW's exhibited low dispersion     

Microwave circuit theory-based models to predict the resonant frequencies of a wide range of ring resonators

The concept of the ring resonance of a symmetric two-port network is used to determine the resonant frequencies of a variety of ring resonators, on the basis of simple transmission-line or coupled-transmission-line equivalent circuits. Several illustrative structures, from the closed ring microstrip to the Pendry-type split-ring slotline resonators, have been analysed and measured. Full-wave simulations and measurements are in excellent agreement with the proposed models, and even with its short-line approximations, when suitable.     

Observation of harmonic gyro-backward-wave oscillation in a 100 GHz CARM oscillator experiment

A cyclotron autoresonance maser (CARM) oscillator experiment is reported, using a 600 keV 200 A electron beam and a whispering-gallery-mode rippled-wall Bragg cavity. This device was designed to produce tens of megawatts of radiation at 100 GHz from a CARM interaction, but instead produced only moderate powers (tens of kilowatts) in fundamental gyrotron modes near 35 GHZ, in third-harmonic gyro-BWO modes and possibly third-harmonic gyrotron modes, at frequencies near the expected CARM frequency, with no discernable CARM radiation. The lack of observable CARM radiation is attributed to excessive ripple on the voltage waveform and to mode competition. Calculations of the spectrum and growth rate of the backward-wave oscillations are consistent with the experimental observation.     

Multiband BPF with wide upper stop band using asymmetrically positioned stub loaded open loop resonators

In this paper, asymmetrically positioned stub loaded open loop resonators with pseudo interdigital coupling are used to design compact multiband planar bandpass filters. The first design pertains to a dualband BPF that operates at 3.5 GHz and 5.7 GHz. The parameters like position of stub, which quantifies the asymmetry, and length of stub are further optimised using real coded genetic algorithm to evolve a triband BPF. The evolutionary design procedure is supported with an example of triband BPF having passband at 3.5 GHz, 5.5 GHz and 6.8 GHz, respectively. The transmission line models for both filters are developed as well as fabricated prototypes are realised and tested. There is a good agreement between the measured and simulated results. The measured insertion loss at first and second band centred around 3.5 GHz and 5.7 GHz of the dual band BPF are 1.5 dB and 1.25 dB, respectively. For the triband BPF the values are 1.24 dB, 1.6 dB and 1.8 dB at 3.5, 5.5 and 6.8 GHz, respectively. The dualband design covers the WiMAX and IEEE 802.11a bands where as the triband design also covers the 6.8 GHz RFID frequency.     

A 100 MHz to 1 GHz Variable Gain Amplifier in a 8 GHz 1.2 µm BiCMOS Process

A variable gain amplifier with linear gain control has been implemented in a commercially available 8 GHz 1.2 µm BiCMOS process. The gain adjustment linearization is based on forcing a linearly controllable current through diode-connected transistors, thus generating an internal logarithmic control voltage for the Gilbert-type variable gain cell. A Cherry-Hopper type gain stage is used to provide most of the available gain. Thus, the maximum differential gain is 10 dB with over 1 GHz bandwidth and –6.9 dBm input –-1 dB compression power. Gain adjustment range of 50 dB at 200 MHz and 38 dB at 960 MHz is reported. The chip area is 1.15 × 2.15 mm and it consumes 40 mA from a 5 V supply.     

Cold tests of open coaxial resonators in the range 9–17 GHz

A study of selective properties of coaxial open cylindrical resonators have been conducted experimentally and compared with theory. The resonator consists of an inner circular cylinder symmetrically located inside an outer weakly irregular open waveguide. Several fundamental TE modes were identified over the range 9 to 17 GHz through measurements of the resonant frequencies and the associated loaded quality factors. It has been verified that the structure and the number of resonant modes are both strongly dependent on the diameter of the coaxial insert. Such an electrodynamical system proves to be useful in guided wave applications requiring, for example, filters, frequency-tunable resonators and devices for analyzing the modal composition of a signal.     

77 GHz汽车角雷达宽波束平坦增益阵列天线设计

设计了一款基于波束赋形技术的宽波束、平坦增益平面阵列天线,用于汽车角雷达系统.该阵列天线由三个1×10串馈线阵组成,串馈线阵采用单元不等间距分布的Dolph-Chebyshev天线综合法进行设计以降低副瓣.为了满足汽车角雷达宽视场角(field of view,FOV)的需求,对平面阵列天线采用波束赋形技术以展宽方位面...