W-Band Active Down-Conversion Mixer in Bulk CMOS

A W-band (76–77 GHz) active down-conversion mixer has been demonstrated using low leakage (higher ${rm V}_{{rm T}}$) NMOS transistors of a 65-nm digital CMOS process with 6 metal levels. It achieves conversion gain of ${-}8$ dB at 76 GHz with a local oscillation power of 4 dBm (${sim-}2$ dBm after de-embedding the on-chip balun loss), and 3 dB bandwidth of 3 GHz. The SSB noise figures are 17.8–20 dB (11.3–13.5 dB after de-embedding on-chip input balun loss) between 76 and 77 GHz. ${rm IP}_{1{rm dB}}$ is ${-}6.5$ dBm and IIP3 is 2.5 dBm (${sim-}13$ and ${sim}-4$ dBm after de-embedding the on-chip balun loss). The mixer consumes 5 mA from a 1.2 V supply.      

2 MHz AO $Q$ -switched ${rm TEM}_{00}$ Grazing Incidence Laser With 3 at.% Neodymium Doped Nd:YVO$_{4}$

We present a detailed experimental and theoretical study of the ultrahigh repetition rate AO $Q$ -switched ${rm TEM}_{00}$ grazing incidence laser. Up to 2.1 MHz $Q$-switching with ${rm TEM}_{00}$ output of 8.6 W and 2.2 MHz $Q$ -switching with multimode output of 10 W were achieved by using an acousto-optics $Q$ -switched grazing-incidence laser with optimum grazing-incidence angle and cavity configuration. The crystal was 3 at.% neodymium doped Nd:YVO$_{4}$ slab. The pulse duration at 2 MHz repetition rate was about 31 ns. The instabilities of pulse energy at 2 MHz repetition rate were less than ${pm}6.7hbox{%}$ with ${rm TEM}_{00}$ operation and ${pm}3.3hbox{%}$ with multimode operation respectively. The modeling of high repetition rate $Q$-switched operation is presented based on the rate equation, and with the solution of the modeling, higher pump power, smaller section area of laser mode, and larger stimulated emission cross section of the gain medium are beneficial to the $Q$-switched operation with ultrahigh repetition rate, which is in consistent with the experimental results.      

Q-Band pHEMT and mHEMT Subharmonic Gilbert Upconversion Mixers

This letter makes a comparison between Q-band 0.15 $mu{rm m}$ pseudomorphic high electron mobility transistor (pHEMT) and metamorphic high electron mobility transistor (mHEMT) stacked-LO subharmonic upconversion mixers in terms of gain, isolation and linearity. In general, a 0.15 $mu{rm m}$ mHEMT device has a higher transconductance and cutoff frequency than a 0.15 $mu{rm m}$ pHEMT does. Thus, the conversion gain of the mHEMT is higher than that of the pHEMT in the active Gilbert mixer design. The Q-band stacked-LO subharmonic upconversion mixers using the pHEMT and mHEMT technologies have conversion gain of $-$7.1 dB and $-$0.2 dB, respectively. The pHEMT upconversion mixer has an ${rm OIP}_{3}$ of $-$12 dBm and an ${rm OP}_{1 {rm dB}}$ of $-$24 dBm, while the mHEMT one shows a 4 dB improvement on linearity for the difference between the ${rm OIP}_{3}$ and ${rm OP}_{1 {rm dB}}$. Both the chip sizes are the same at 1.3 mm $times$ 0.9 mm.      

Analysis and Design of a CMOS UWB LNA With Dual- -Branch Wideband Input Matching Network

A wideband low-noise amplifier (LNA) based on the current-reused cascade configuration is proposed. The wideband input-impedance matching was achieved by taking advantage of the resistive shunt–shunt feedback in conjunction with a parallel LC load to make the input network equivalent to two parallel $RLC$-branches, i.e., a second-order wideband bandpass filter. Besides, both the inductive series- and shunt-peaking techniques are used for bandwidth extension. Theoretical analysis shows that both the frequency response of input matching and noise figure (NF) can be described by second-order functions with quality factors as parameters. The CMOS ultra-wideband LNA dissipates 10.34-mW power and achieves ${ S}_{11}$ below $-$8.6 dB, ${ S}_{22}$ below $-$10 dB, ${ S}_{12}$ below $-$26 dB, flat ${ S}_{21}$ of 12.26 $pm$ 0.63 dB, and flat NF of 4.24 $ pm$ 0.5 dB over the 3.1–10.6-GHz band of interest. Besides, good phase linearity property (group-delay variation is only $pm$22 ps across the whole band) is also achieved. The analytical, simulated, and measured results agree well with one another.      

Low-Threshold Strained Quantum-Well GaSb-Based Lasers Emitting in the 2.5- to 2.7-$mu$ m Wavelength Range

GaInAsSb–GaSb strained quantum-well (QW) ridge waveguide diode lasers emitting in the wavelength range from 2.51 to 2.72 $ mu{hbox {m}}$ have been grown by molecular beam epitaxy. The devices show ultralow threshold current densities of 44 $hbox{A}/{hbox {cm}}^{2}$ (${L}rightarrow infty $) for a single QW device at 2.51 $ mu{hbox {m}}$, which is the lowest reported value in continuous-wave operation near room temperature (15 $^{circ}hbox{C}$) at this wavelength. The devices have an internal loss of 3 ${hbox {cm}}^{-1}$ and a characteristic temperature of 42 K. By using broader QWs, wavelengths up to 2.72 $mu{hbox {m}}$ could be achieved.      

Extended Fault-Tolerant Cycle Embedding in Faulty Hypercubes

We consider fault-tolerant embedding, where an $n$-dimensional faulty hypercube, denoted by $Q_{n}$, acts as the host graph, and the longest fault-free cycle represents the guest graph. Let $F_{v}$ be a set of faulty nodes in $Q_{n}$. Also, let $F_{e}$ be a set of faulty edges in which at least one end-node of each edge is faulty, and let ${cal F}_{e}$ be a set of faulty edges in which the end-nodes of each edge are both fault-free. An edge in $Q_{n}$ is said to be critical if it is either fault-free or in $F_{e}$. In this paper, we prove that there exists a fault-free cycle of length at least $2^{n}-2vert F_{v}vert$ in $Q_{n} (ngeq 3)$ with $vert{cal F}_{e}vertleq 2n-5$, and $vert F_{v}vert+vert{cal F}_{e}vertleq 2n-4$ , in which each node is incident to at least two critical edges. Our result improves on the previously best known results reported in the literature, where only faulty nodes or faulty edges are considered.      

Zn$_{1 - x}$Mg$_{x}$ O Homojunction-Based Ultraviolet Photodetector

Zn$_{1 - {x}}$ Mg$_{x}$ O p-n photodiodes were fabricated on (0001) sapphire substrates using a pulsed laser deposition technique with different Mg contents. Ti–Au and Ni–Au metals deposited using vacuum evaporation were used as n-type and p-type contacts, respectively. The X-ray diffraction analysis showed the Zn$_{1 - {x}}$Mg$_{x}$O double layers have a single phase hexagonal wurtzite structure. The optical bandgap of Zn$_{1 - {x}}$Mg$_{x}$O films has been tuned from 3.27 to 4.26 eV by increasing the Mg content ${x} =0.0$ to ${x}=0.34$. Correspondingly, the cutoff wavelength of the resultant detectors varies from 380 to 284 nm. Zn$_{1 - {x}}$Mg$_{x}$O p-n photodiodes with different Mg contents exhibit very good performance, with a very low dark current (${≪}$ 20 pA) at the bias voltage of 10 V. The ultraviolet to visible rejection ratio is more than three orders of magnitude.      

A 36–80 GHz High Gain Millimeter-Wave Double-Balanced Active Frequency Doubler in SiGe BiCMOS

This letter presents a high conversion gain double-balanced active frequency doubler operating from 36 to 80 GHz. The circuit was fabricated in a 200 GHz ${rm f}_{rm T}$ and ${rm f}_{max}$ 0.18 $mu$m SiGe BiCMOS process. The frequency doubler achieves a peak conversion gain of 10.2 dB at 66 GHz. The maximum output power is 1.7 dBm at 66 GHz and ${-}3.9$ dBm at 80 GHz. The maximum fundamental suppression of 36 dB is observed at 60 GHz and is better than 20 dB from 36 to 80 GHz. The frequency doubler draws 41.6 mA from a nominal 3.3 V supply. The chip area of the active frequency doubler is 640 $mu$m $,times,$424 $mu$m (0.272 mm $^{2}$) including the pads. To the best of authors' knowledge, this active frequency doubler has demonstrated the highest operating frequency with highest conversion gain and output power among all other silicon-based active frequency doublers reported to date.      

Performance Improvement of N-Type $hbox{TiO}_{x}$ Active-Channel TFTs Grown by Low-Temperature Plasma-Enhanced ALD

We report on performance improvement of $n$-type oxide–semiconductor thin-film transistors (TFTs) based on $hbox{TiO}_{x}$ active channels grown at 250 $^{circ}hbox{C}$ by plasma-enhanced atomic layer deposition. TFTs with as-grown $hbox{TiO}_{x}$ films exhibited the saturation mobility $(mu_{rm sat})$ as high as 3.2 $hbox{cm}^{2}/hbox{V}cdothbox{s}$ but suffered from the low on–off ratio $(I_{rm ON}/I_{rm OFF})$ of $hbox{2.0} times hbox{10}^{2}$. $hbox{N}_{2}hbox{O}$ plasma treatment was then attempted to improve $I_{rm ON}/I_{rm OFF}$. Upon treatment, the $hbox{TiO}_{x}$ TFTs exhibited $I_{rm ON}/I_{rm OFF}$ of $hbox{4.7} times hbox{10}^{5}$ and $mu_{rm sat}$ of 1.64 $hbox{cm}^{2}/hbox{V}cdothbox{s}$, showing a much improved performance balance and, thus, demonstrating their potentials for a wide variety of applications such as backplane technology in active-matrix displays and radio-frequency identification tags.      

1580-V–40-$hbox{m}Omegacdot hbox{cm}^{2}$ Double-RESURF MOSFETs on 4H-SiC $(hbox{000}bar{hbox{1}})$

Double-reduced-surface-field (RESURF) MOSFETs with $hbox{N}_{2}hbox{O}$ -grown oxides have been fabricated on the 4H-SiC $(hbox{000} bar{hbox{1}})$ face. The double-RESURF structure is effective in reducing the drift resistance, as well as in increasing the breakdown voltage. In addition, by utilizing the 4H-SiC $(hbox{000}bar{hbox{1}})$ face, the channel mobility can be increased to over 30 $hbox{cm}^{2}/hbox{V}cdothbox{s}$, and hence, the channel resistance is decreased. As a result, the fabricated MOSFETs on 4H-SiC $( hbox{000}bar{hbox{1}})$ have demonstrated a high breakdown voltage $(V_{B})$ of 1580 V and a low on-resistance $(R_{rm ON})$ of 40 $hbox{m}Omega cdothbox{cm}^{2}$. The figure-of-merit $(V_{B}^{2}/R_{rm ON})$ of the fabricated device has reached 62 $hbox{MW/cm}^{2}$, which is the highest value among any lateral MOSFETs and is more than ten times higher than the “Si limit.”      

Universal Lossless Compression of Erased Symbols

A source ${mmb X}$ goes through an erasure channel whose output is ${mmb Z}$. The goal is to compress losslessly ${mmb X}$ when the compressor knows ${mmb X}$ and ${mmb Z}$ and the decompressor knows ${mmb Z}$. We propose a universal algorithm based on context-tree weighting (CTW), parameterized by a memory-length parameter $ell$. We show that if the erasure channel is stationary and memoryless, and ${mmb X}$ is stationary and ergodic, then the proposed algorithm achieves a compression rate of $H(X_0vert X_{-ell}^{-1}, Z^ell)$ bits per erasure.      

Improved Microwave Noise Performance by SiN Passivation in AlGaN/GaN HEMTs on Si

Effects of silicon nitride (SiN) surface passivation by plasma enhanced chemical vapor deposition (PECVD) on microwave noise characteristics of AlGaN/GaN HEMTs on high-resistivity silicon (HR-Si) substrate have been investigated. About 25% improvement in the minimum noise figure $(NF_{min})$ (0.52 dB, from 2.03 dB to 1.51 dB) and 10% in the associate gain $(G_{rm a})$ (1.0 dB, from 10.3 dB to 11.3 dB) were observed after passivation. The equivalent circuit parameters and noise source parameters (including channel noise coefficient $(P)$, gate noise coefficient $(R)$, and their correlation coefficient $(C)$ ) were extracted. $P$ , $R$ and $C$ all increased after passivation and the increase of C contributes to the decrease of the noise figure. It was found that the improved microwave small signal and noise performance is mainly due to the increase of the intrinsic transconductance $(g_{{rm m}0})$ and the decrease of the extrinsic source resistance $(R_{rm s})$.      

An Edge Missing Compensator for Fast Settling Wide Locking Range Phase-Locked Loops

An edge missing compensator (EMC) is proposed to approach the function of an ideal PD with $pm 2 ^{N-1} times 2pi $ linear range with $N$-bit EMC. A PLL implemented with a 9-bit EMC achieves 320 MHz frequency hopping within 10 $~mu{hbox {s}}$ logarithmically which is about 2.4 times faster than the conventional design. The reference spur of the PLL is ${-}{hbox {48.7~dBc}}$ and the phase noise is ${-}hbox{88.31~dBc/Hz}$ at 10 kHz offset with $K_{rm VCO}= -$ 2 GHz/V.      

Fast Characterization of Threshold Voltage Fluctuation in MOS Devices

Random microscopic fluctuations in the number and location of dopant atoms can cause a large variation in the threshold voltage $(V _{T})$ of a MOS device. In this paper, we present a technique for fast characterization of random threshold voltage mismatch in MOS devices. Our $V _{T}$ scatter characterization method measures threshold voltage shift by monitoring the change in gate-to-source voltage $V _{GS}$ for a fixed drain current $I _{DS}$ and drain-to-source voltage $V _{DS}$ . We present circuit schematics to characterize $V _{T}$ scatter by measuring $V _{GS}$ variation for a large set of devices arranged in an individually addressable array. We report experimental results of $V _{T}$ scatter measurement from test chips fabricated in 65-nm silicon-on-insulator and 65-nm bulk CMOS processes. We also measure and report the magnitude of local device current mismatch caused by $V _{T}$ fluctuation.      

The Impact of Oxide Traps Induced by SOI Thickness on Reliability of Fully Silicide Metal-Gate Strained SOI MOSFET

In this letter, we investigate the effects of oxide traps induced by various silicon-on-insulator (SOI) thicknesses $({T}_{rm SOI})$ on the performance and reliability of a strained SOI MOSFET with SiN-capped contact etch stop layer (CESL). Compared to the thicker ${T}_{rm SOI}$ device, the thinner ${T}_{rm SOI}$ device with high-strain CESL possesses a higher interface trap $({N}_{rm it})$ density, leading to degradation in the device performance. On the other hand, however, the thicker ${T}_{rm SOI}$ device reveals inferior gate oxide reliability. From low-frequency noise analysis, we found that thicker ${T}_{rm SOI}$ has a higher bulk oxide trap $({N}_{rm BOT})$ density, which is induced by larger strain in the gate oxide film and is mainly responsible for the inferior TDDB reliability. Presumably, the gate oxide film is bended up and down for the p- and nMOSFETs, respectively, by the net stress in thicker ${T}_{rm SOI}$ devices in this strain technology.      

Compact Microracetrack Resonator Devices Based on Small SU-8 Polymer Strip Waveguides

Compact microracetrack resonator (MRR) devices are presented with small SU-8 polymer strip waveguides. The SU-8 strip waveguide has an SU-8 polymer core $(n {sim} 1.573)$ , a SiO$_{2}$ buffer $(n {sim} 1.445)$, and an air cladding. The fabricated straight waveguide has a low propagation loss of about 0.1 dB/mm. With such a high index-contrast optical waveguide, a compact MRR with a small bending radius ( $sim$150 $mu$m) are designed and fabricated. The measured spectral responses of the through/drop ports show a $Q$-factor of 8000.      

Single- and Dual-Polarized Tunable Slot-Ring Antennas

Single- and dual-polarized slot-ring antennas with wideband tuning using varactor diodes have been demonstrated. The single-polarized antenna tunes from 0.95 to 1.8 GHz with better than ${-}13$ dB return loss. Both polarizations of the dual-polarized antenna tune from 0.93 to 1.6 GHz independently with better than ${-}10$ dB return loss and $> !20!$ dB port-to-port isolation over most of the tuning range. The capacitance of the varactor diodes varies from 0.45 to 2.5 pF, and the antennas are printed on 70 $,times,$70 $,times,$0.787 mm ${^3}$ substrates with ${epsilon_{rm r} = 2.2}$. The dual-polarized slot-ring antenna can either be made both frequency- and polarization-agile simultaneously, or can operate at two independent frequencies on two orthogonal polarizations. To our knowledge, this is the first dual-polarized tunable antenna with independent control of both polarizations over a 1.7:1 frequency range.      

A 0.55 V 60 dB-DR Fourth-Order Analog Baseband Filter

A 0.55 V supply voltage fourth-order low-pass continuous-time filter is presented. The low-voltage operating point is achieved by an improved bias circuit that uses different opamp input and output common-mode voltages. The fourth-order filter architecture is composed by two Active- ${rm G}_{rm m}{-}{rm RC}$ biquadratic cells, which use a single opamp per-cell with a unity-gain-bandwidth comparable to the filter cut-off frequency. The $-$ 3 dB filter frequency is 12 MHz and this is higher than any other low-voltage continuous-time filter cut-off frequency. The $-$3 dB frequency can be adjusted by means of a digitally-controlled capacitance array. In a standard 0.13 $mu{rm m}$ CMOS technology with ${V}_{THN}approx 0.25 {rm V}$ and ${V}_{THP}approx 0.3 {rm V}$, the filter operates with a supply voltage as low as 0.55 V. The filter $({rm total} {rm area}=0.47 {rm mm}^{2})$ consumes 3.4 mW. A 8 dBm-in-band IIP3 and a 13.3 dBm-out-of-band IIP3 demonstrate the validity of the proposal.      

A 0.13 $mu$ m CMOS Quad-Band GSM/GPRS/EDGE RF Transceiver Using a Low-Noise Fractional-N Frequency Synthesizer and Direct-Conversion Architecture

This paper presents a single-chip CMOS quad-band (850/900/1800/1900 MHz) RF transceiver for GSM/GPRS/EDGE applications which adopts a direct-conversion receiver, a direct-conversion transmitter and a fractional-N frequency synthesizer with a built-in DCXO. In the GSM mode, the transmitter delivers 4 dBm of output power with 1$^{circ}$ RMS phase error and the measured phase noise is ${-}$164.5 dBc/Hz at 20 MHz offset from a 914.8$~$MHz carrier. In the EDGE mode, the TX RMS EVM is 2.4% with a 0.5 $~$dB gain step for the overall 36 dB dynamic range. The RX NF and IIP3 are 2.7 dB/ ${-}$12 dBm for the low bands (850/900 MHz) and 3 dB/${-}$ 11 dBm for the high bands (1800/1900 MHz). This transceiver is implemented in 0.13 $mu$m CMOS technology and occupies 10.5 mm$^{2}$ . The device consumes 118 mA and 84 mA in TX and RX modes from 2.8 V, respectively and is housed in a 5$,times,$ 5 mm$^{2}$ 40-pin QFN package.      

Temperature-Insensitive Dual-Comb Filter Based on Multimode Interference Ti : LiNbO $_{3}$ Waveguide

A temperature-insensitive dual-comb filter has been demonstrated for the first time by multimode interference based on a Ti : LiNbO$_{3}$ channel waveguide. The phase difference between comb filters was about 180 $^{circ}$. We only observed less than ${pm}$0.125-nm variation of the center wavelength of the filter during temperature change from 20 $^{circ}$C to 50 $^{circ}$C. The measured extinction ratio and channel spacing of the comb filter were about ${-}$25 dB and 3.2 THz, respectively.