InP 双异质结晶体管工艺ROM-Less 架构14 GHz DDS

介绍了采用ft/fmax 为250/280 GHz 的0.7μm InP 双异质结晶体管工艺的14 GHz 8bit ROM-Less 直接数字频率合成器。电路采用正弦加权非线性数模转换器实现了一种ROM-Less 相幅转换,充分发挥了InP-DHBT 技术在中大规模混合信号集成电路中的速度优势。为降低功耗,采用了简化的流水线相位累加器。在整个频率控制字范围内,测试得到的平均无杂散动态范围为24.8 dBc。该电路由2122 个晶体管组成,功耗为2.4 W,其优值系数为5.83 GHz/ W。     

A 16–46 GHz Mixer Using Broadband Multilayer Balun in 0.18-μm CMOS Technology

A 16-46 GHz mixer using broadband balun fabricated in standard 0.18-mum CMOS process is demonstrated. The broadside-coupled balun with wide bandwidth and low insertion loss utilizes the inherent 3D multilayer structure in CMOS process. The mixer exhibits radio frequency bandwidth from 16 to 46 GHz with a conversion loss ranging from 13 plusmn 1.5 dB, and achieves bandwidth over 103% with a compact chip size of 0.24 mm².     

A 12 GHz 1.9 W Direct Digital Synthesizer MMIC Implemented in 0.18 $mu$m SiGe BiCMOS Technology

This paper presents a 12 GHz direct digital synthesizer (DDS) MMIC with 9-bit phase and 8-bit amplitude resolution implemented in a 0.18 mum SiGe BiCMOS technology. Composed of a 9-bit pipeline accumulator and an 8-bit sine-weighted current-steering DAC, the DDS is capable of synthesizing sinusoidal waveforms up to 5.93 GHz. The maximum clock frequency of the DDS MMIC is measured as 11.9 GHz at the Nyquist output and 12.3 GHz at 2.31 GHz output. The spurious-free dynamic range (SFDR) of the DDS, measured at Nyquist output with an 11.9 GHz clock, is 22 dBc. The power consumption of the DDS MMIC measured at a 12 GHz clock input is 1.9 W with dual power supplies of 3.3 V/4 V. The DDS thus achieves a record-high power efficiency figure of merit (FOM) of 6.3 GHz/W. With more than 9600 transistors, the active area of the MMIC is only 2.5 x 0.7 mm². The chip was measured in packaged prototypes using 48-pin ceramic LCC packages.     

Effects of Doping Profile on GaAs, Double-Drift IMPATT Diodes at 33 and 44 GHz Using the Energy-Momentum Transport Model

Experimentally determined doping profiles for double-read GaAs IMPATT diodes operating at 33 and 44 GHz are used as starting points for a computer optimization. A computer simulation including energy and momentum relaxation effects was used to simulate these devices as the lengths of the drift regions and the integrated charge in the doping spikes were varied. The effects of these doping profile variations on diode performance are presented.     

Direct Phase Regeneration of a 400 Mbit/s QPSK Signal at 1.7 GHz

A theoretical analysis is presented for a multi-hop relay system composed of QPSK-DPR's. A Direct Phase Regenerator (DPR) can regenerate a QPSK signal at carrier frequency. Special attention is given to jitter generation and accumulation. Circuit parameters characterizing jitter generation are clarified and obtained quantitatively. The required upper limit for jitter per DPR is also obtained from allotedC/Ndegradation in a multi-hop system. Simulation experiments were carried out using a novel 400 Mbit/s QPSK-DPR with less than 1 dB inherent equivalentC/Ndegradation. The results Show that a hybrid system, consisting of 4 to 9 DPR's and a base band regenerator, is feasible.     

Mutual Coupling Reduction in Patch Antenna Arrays by Using a Planar EBG Structure and a Multilayer Dielectric Substrate

Periodic structures can help in the reduction of mutual coupling by using their capability of suppressing surface waves propagation in a given frequency range. The purpose of this work is to show the viability of using a planar electromagnetic band gap (EBG) structure based on a truncated frequency selective surface (FSS) grounded slab to this aim. The goal is to use it in patch antenna arrays, keeping both the element separation smaller than for grating lobes avoidance (assuming broadside case) and the patch antenna size large enough to have a good antenna directivity. To this aim, a multilayer dielectric substrate composed of high and low permittivity layers is convenient. This allows the use of a planar EBG structure made of small elements printed on the high permittivity material and, at the same time, the low permittivity layer helps the bandwidth and the directivity of the antenna to be increased. The EBG structure was designed under these premises and optimized for the particular application via an external optimization algorithm based on evolutionary computation: ant colony optimization (ACO). The mutual coupling reduction has been measured and it is larger than 10 dB with a completely planar structure.     

Efficient Full-Wave Analysis of Multilayer Interconnection Structures Using a Novel Domain Decomposition–Model-Order Reduction Method

A novel domain decomposition-model-order reduction method is proposed for efficient full-wave finite-element analysis of multilayer interconnection structures. By considering the special properties of a multilayer structure, the field at each nonmetallic interface (via-holes or other apertures) can be approximated with a modal expansion to establish a boundary condition and decompose the entire computational domain into separate layers. The coupling between each dielectric layer is taken into account through a mode-matching process. To further speed up the computation in each layer, the solution space projection, which is a multipoint model-order reduction method, is integrated into the aforementioned domain decomposition method to form a complete solution algorithm. With the aid of reduced-order models, the domain decomposition process at each frequency is accelerated and a fast broadband analysis is achieved. This domain decomposition-model-order reduction method, called approximate modal interface-solution space projection, is implemented using the finite-element method and validated through several examples, which demonstrate the efficiency of the method in both the computation time and memory usage.     

Reduction of Power Fluctuation in ECMA-368 Ultra Wideband Communication Systems Using Multilayer Perceptron Neural Networks

ECMA-368 Ultra Wideband (UWB) wireless communication Standard adopts Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) technology to transmit information with high data rate (480 Mbits/s). However, the high Peak to Average Power Ratio of MB-OFDM UWB signals, limits the power efficiency of the high power amplifier due to nonlinear distortion. In order to avoid this drawback, an efficient scheme based on multilayer perceptron, artificial neural networks is proposed. The neural network is adjusted by using active constellation extension technique which provides satisfactory results. This proposed solution gives good performance compared to previously available methods with much lower complexity, without iterations, good bit error rate and no increase in transmitted signal power and bandwidth.     

Measurements of Ohmic Losses of Metallic Reflectors at 140 GHz Using a 3-Mirror Resonator Technique

The reflectivity of metallic mirrors in the millimeter wave region does not only depend on the material, but also on the structure and roughness of the surface. We have performed measurements of the reflectivity of various plane and grooved metallic and graphite samples at 140 GHz. The technique is based on the comparison of the quality factor of a 2-mirror reference resonator with the quality factor of a 3-mirror resonator which has identical dimensions and includes the mirror to be tested. After a brief presentation of the theory, the set-up is described and the reflection loss for various aluminium and copper mirrors as well as vacuum compatible materials for applications in thermonuclear fusion experiments are presented and discussed.     

Detection of Concealed Explosives at a Distance Using Terahertz Technology

Terahertz imaging and spectroscopy has been shown to have the potential to use very low levels of nonionizing radiation to detect and identify objects hidden under clothing. In this paper we discuss some of the important factors involved in addressing practical systems in the security industry, and describe our recent work on the development of a prototype terahertz standoff detection system. Using this system we demonstrate the spectroscopic detection of concealed explosives at a standoff distance of 1 m, both real time, in reflection, and under normal atmospheric conditions.     

Parallel Plate Cavity Mode Suppression in Microstrip Circuit Packages Using a Lid of Nails

The suppression of parallel plate and cavity modes in shielded microstrip circuits is presented. To this aim a textured metal lid consisting of periodically located pins known as a bed of nails is employed. The mode suppression has a bandwidth of more than 2:1, and it does not interfere much with the microstrip circuit. Thereby, this mode suppression technique introduces a new advantageous packaging technology for high frequency circuits.      

Design of a 24 GHz, 25-50 kW Technology Gyrotron Operating at the Second Harmonic

The preliminary design of a moderate (25-50 kW) gyrotron operating at the ISM (industrial, scientific, medical) frequency of 24.1 GHz is presented. Operation at the second harmonic is considered so that one can obtain radiation at the given frequency with only half the magnetic field required.     

Propagation at 2.0 GHz in an Enclosed Area Using a Coaxial Cable with Leaky Sections as the Transmitting Antenna

This paper presents the results of narrowband and wideband propagation measurements carried out at 2.0 GHz in a large enclosed area using a coaxial cable with leaky sections as the transmitting antenna. The narrowband measurements were devised to measure attenuation of radio signals and the wideband techniques to measure multipath impulse responses and their associated root mean square delay spread. Analysis of the narrowband data files shows that the received signal levels in the direction parallel to the cable generally decay and display peaks in front of leaky sections due to the specific attenuation and special structure of the cable. The received signal levels in the direction radial to the cable decrease slowly and the distance-power law exponent is found to be slightly larger than one. The slow and fast variations of the received signal levels are also examined. The results reveal that the slow variations do not follow the lognormal distribution, while the fast variations fit the Rayleigh distribution in both parallel and radial directions. Analysis of the wideband data files yields that the maximum value of the root mean square delay spread is 86.1 ns and the root mean square delay spread values are less than 55 ns 50% of the time. One therefore can conclude that the enclosed area channel excited by the coaxial cable with leaky sections has a broad coherent bandwidth and can support the data rate up to 2.3 Mb/s without equalization.     

Silicon-on-Organic Integration of a 2.4–GHz VCO Using High-Q Copper Inductors and Solder-Bumped Flip Chip Technology

High-Q copper inductors were fabricated on low-cost and low-loss bismaleimide triazine (BT) and glass substrate using electroplating process. A differential LC voltage-controlled oscillator (VCO) circuit was designed using these high-Q inductors at 2.4 GHz. Flip chip and multichip module (MCM) technologies were applied to assemble the active chips on BT and glass substrate. The inductors exhibited Q-factor as high as 25 at 2.4 GHz. VCOs with copper inductors on BT and glass substrate had phase noise of $-$108 dBc/Hz at 600 kHz offset for a 2.4-GHz carrier, which is 6-dB improvement compared with the one with on-chip Al inductors. There was almost no substrate loss for inductors on BT and glass substrates. The effect of fabrication defects and solder joint resistance were also investigated. This technique can be extended to other building blocks, thus realizing integration of the whole RF system.      

Improved Synthesis of Superconducting Carbon-Doped MgB2 Using a Biopolymer for Simultaneous Crystallite Size Control and Chemical Reduction

This study represents a key evolution in the synthesis of the superconductor MgB₂, as it is the first to demonstrate that templated synthesis can be carried out successfully without a sealed reaction vessel. This is possible owing to the strong chelating ability of the biopolymer dextran, whose morphological complexity effectively cocoons the reaction, preventing oxygen ingress. This synthetic protocol demonstrates that not only can this important material be synthesized as nanoparticles but that, as the morphological template is calcined, it effectively carbon-dopes the superconducting phase, thereby improving the critical current density by a factor of five.     

Analysis of Rain-Induced Attenuation at Ku-V Band Using Gamma Drop Size Distribution Model Over a Tropical Region

Wireless Personal Communications - In this paper, modeling of rain drop size distribution (DSD) and analysis of rain-induced attenuation are analyzed based on Gamma DSD model in a tropical...     

100 GHz+ Gain-Bandwidth Differential Amplifiers in a Wafer Scale Heterogeneously Integrated Technology Using 250 nm InP DHBTs and 130 nm CMOS

Differential amplifiers incorporating the advantages of both Si and III-V technologies have been fabricated in a wafer scale, heterogeneously integrated, process using both 250 nm InP DHBTs and 130 nm CMOS. These ICs demonstrated gain-bandwidth product of 40-130 GHz and low frequency gain > 45 dB . The use of InP DHBTs supports a > 6.9 V differential output swing and a slew rate > 4 times 10⁴V/mus to be achieved with as low as 40 mW dissipated power. A novel on-chip buffer circuit is used to facilitate the on-wafer characterization of these amplifiers. To the authors' knowledge, this is the first demonstration of a high performance IC building block in a heterogeneously integrated process technology.     

Effect of Sputtered ZnO Layers on Behavior of Thin-Film Transistors Deposited at Room Temperature in a Nonreactive Atmosphere

In this work we present the electrical characterization of ZnO-based thin-film transistors fabricated at room temperature. The ZnO films were deposited by radiofrequency magnetron sputtering at variable argon pressure (3 mTorr to 10 mTorr) at room temperature. The sputtered ZnO films were polycrystalline with hexagonal structure and electrical resistivity ranging from 10¹ Ω cm to 10⁸ Ω cm for films deposited from 3 mTorr to 10 mTorr. The trend in the electrical behavior of the devices was found to be due to the variation of the electron concentration of the ZnO films. The devices with better performance showed a field-effect mobility of 2.9 cm²/Vs, threshold voltage of 20 V, I _on/I _off ≈ 10⁶, and electrical resistivity of ~10⁸ Ω cm. In addition, linear behavior of I _on/I _off with deposition pressure was observed. The lowest I _on/I _off ratio (~2) was calculated for devices with ZnO layers deposited at 3 mTorr, and the highest ratio (~10⁶) for devices processed at 10 mTorr. Hall-effect measurements were performed on ZnO films showing the lowest resistivity. The layer grown at 3 mTorr showed a Hall mobility of μ _H = 8.9 cm²/Vs and carrier concentration of n = 4.2 × 10¹⁶ cm⁻³ with resistivity of ρ = 31.8 Ω cm. For films deposited at 5 mTorr, the Hall mobility, carrier concentration, and resistivity were μ _H = 7.9 cm²/Vs, n = 3.4 × 10¹⁶ cm⁻³, and ρ = 38.4 Ω cm, respectively. Films deposited at 8 mTorr and 10 mTorr could not be measured due to their high resistance.     

Testing of a 1.5-m reflector antenna at 322 GHz in a CATR based on a hologram

Hologram-based compact antenna test range (CATR) is a potential method for testing large antennas at submillimeter wavelengths. This paper describes testing of a 1.5-m single offset parabolic reflector antenna with a 3-m-diameter hologram-based CATR. This is the first time such a measurement is carried out at submillimeter wavelengths. The antenna tests were done in a CATR that was specifically designed and constructed for these tests. The measured radiation pattern at the frequency of 322 GHz is presented. The measured pattern corresponds reasonably well to the simulated pattern of the antenna. The effect of the quiet-zone field nonidealities on the measurement results and the reasons for the discrepancies in the measured antenna beam are discussed.     

Assessment of principal planes orientation in a terrestrial link at 18 GHz during intense rainfall

Simultaneous measurements of attenuation and depolarisation at 18 GHz collected during a propagation experiment on a 9.5 km terrestrial link have been employed to extract information about the angle formed by the principal planes with respect to the vertical-horizontal orientations (canting angle). Tilted polarisation planes have been adopted in order to increase the system sensitivity and to detect the sign of the angle according to a new technique recently devised.