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.      

17 GHz RF Front-Ends for Low-Power Wireless Sensor Networks

A 17 GHz low-power radio transceiver front-end implemented in a 0.25 $mu{hbox {m}}$ SiGe:C BiCMOS technology is described. Operating at data rates up to 10 Mbit/s with a reduced transceiver turn-on time of 2 $mu{hbox {s}}$, gives an overall energy consumption of 1.75 nJ/bit for the receiver and 1.6 nJ/bit for the transmitter. The measured conversion gain of the receiver chain is 25–30 dB into a 50 $Omega$ load at 10 MHz IF, and noise figure is 12 $pm$0.5 dB across the band from 10 to 200 MHz. The 1-dB compression point at the receiver input is $-$37 dBm and ${hbox{IIP}}_{3}$ is $-$25 dBm. The maximum saturated output power from the on-chip transmit amplifier is $-$1.4 dBm. Power consumption is 17.5 mW in receiver mode, and 16 mW in transmit mode, both operating from a 2.5 V supply. In standby, the transceiver supply current is less than 1 $mu{hbox {A}}$.      

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.      

10-GHz and 20-GHz Channel Spacing High-Resolution AWGs on InP

This letter reports on 10-GHz and 20-GHz channel-spacing arrayed waveguide gratings (AWGs) based on InP technology. The dimensions of the AWGs are 6.8$,times,$8.2 mm$^{2}$ and 5.0$,times,$6.0 mm$^{2}$, respectively, and the devices show crosstalk levels of $-$12 dB for the 10-GHz and $-$17 dB for the 20-GHz AWG without any compensation for the phase errors in the arrayed waveguides. The root-mean-square phase errors for the center arrayed waveguides were characterized by using an optical vector network analyzer, and are 18 $^{circ}$ for the 10-GHz AWG and 28$^{circ}$ for the 10-GHz AWG.      

Integrated Quadrature Couplers and Their Application in Image-Reject Receivers

Several fully-integrated multi-stage lumped-element quadrature hybrids that enhance bandwidth, amplitude and phase accuracies, and robustness are presented, and a fully-integrated double-quadrature heterodyne receiver front-end that uses two-stage Lange/Lange couplers is described. The Lange/Lange cascade exploits the inherent wide bandwidth characteristic of the Lange hybrid and enables a robust design using a relatively low transformer coupling coefficient. The measured image-rejection ratio is $>$ 55 dB over a 200 MHz bandwidth centered around 5.25 $~$GHz without any tuning, trimming, or calibration; the front-end features 23.5 dB gain, $-$79 dBm sensitivity, 5.6 dB SSB NF, $-$7$~$ dBm IIP3, $-$18 dB $S_{11}$ and a 1 mm $times$ 2 mm die area in 0.18$ mu{hbox {m}}$ CMOS.      

A Novel Multiloop Optoelectronic Oscillator

We present a novel realization of a multiloop optoelectronic oscillator based on a wavelength multiplexed optical source and fiber Bragg grating reflectors. The oscillator exhibits a phase noise of $-$108 dBc/Hz at 10-kHz offset from the 10.2-GHz carrier while suppressing parasitic modes to below $-$80 dBc.      

125-GHz Diode Frequency Doubler in 0.13-$mu{hbox {m}}$ CMOS

The first mm-wave Schottky diode frequency doubler fabricated in CMOS is demonstrated. The doubler built in 130-nm CMOS uses a balanced topology with two shunt Schottky barrier diodes, and exhibits $sim$10-dB conversion loss as well as $-$1.5-dBm output power at 125 GHz. The input matching is better than $-$10$~$dB from 61 to 66 GHz. The rejection of fundamental signal at output is greater than 12 dB for input frequency from 61 to 66$~$GHz. The doubler can generate signals up to 140 GHz.      

A 60 kb/s–10 Mb/s Adaptive Frequency Hopping Transceiver for Interference-Resilient Body Channel Communication

An interference-resilient 60 kb/s–10 Mb/s body channel transceiver using the human body as a signal transmission medium is designed for multimedia and medical data transaction in body-area network. The body antenna effect which interferes with signals in the human body channel is examined. The body-induced interferences degrade the SIR of the signal to $-$22 dB in the worst case. In order to overcome the body antenna effect, a 4-channel adaptive frequency hopping scheme using the 30–120 MHz band is introduced to the body channel transceiver. A direct-switching modulator using dual frequency synthesizers and a DLL-based demodulator are proposed for 10 Mb/s FSK and the 4.2 $mu hbox{s}$ hopping time. The transceiver fabricated with 0.18 $mu hbox{m}$ CMOS withstands $-$28 dB SIR and its operating distance is over 1.8 m with $-$ 25 dB SIR. Its energy consumption is 0.37 nJ/b with $-$65 dBm sensitivity.      

Separated Unicast/Multicast Splitter-and-Delivery Switch and Its Use in Multicasting-Capable Optical Cross-Connect

We propose a novel separated unicast/multicast splitter-and-delivery (SUM-SaD) switch for mixed unicast and multicast traffic. Only multicast connections undergo extra splitting loss but are compensated by incorporated optical amplifiers. A typical multicasting-capable optical cross-connect is constructed by using the proposed SUM-SaDs. Theoretically, we prove that it is strictly nonblocking for both unicast and multicast connections if $d=N/2$, where $N$ and $d$ are the dimension of SUM-SaD and the number of SaD input ports, respectively. Therefore, $d$ means the maximum accommodated trees in the SUM-SaD. To save cost, $d$ can be less than $N/2$ , and the throughput performance is investigated by simulation. The results show that the throughput is improved when $d$ increases. In the experiment, we construct a 4 $times$ 4 SUM-SaD prototype and measure the bit-error rate (BER) of unicast connection, multicast connection with or without optical amplifier. There is no clear BER difference between them for the small dimensional SUM-SaD switch.      

VCSEL Module With Polymer Optical Output Rods to Enable High Efficiency Coupling for Optical Interconnection

New vertical-cavity surface-emitting laser (VCSEL) modules—designed with a optical output rod surrounded by cladding—have been proposed to realize high-efficiency low-cost optical interconnection. Prototypes have been fabricated using a photomask transfer method employing two kinds of ultraviolet curable resin. Observation of the near-field pattern and eye pattern for signal transmission shows that output rods with a diameter of 50- $mu$m efficiently confine the laser beam as an optical waveguide. In addition, ray tracing simulation indicates that this new VCSEL offers greater positional tolerance—as much as $+$18/ $-$22 $mu$m—for coupling to optical wiring in 90$^{circ}$ light path conversion.      

Work-Function Engineering for 32-nm-Node pMOS Devices: High-Performance TaCNO-Gated Films

We have demonstrated p-type field effect transistors (p-FETs) devices using a TaCNO metal gate for the first time. These p-FETs have threshold voltage values of $-$ 0.4 and $-$ 0.25 V for HfSiON and HfSiO gate dielectrics, respectively, with equivalent oxide thickness of 1.6–1.7 nm. The TaCNO metal shows a high effective work function (eWF) of 4.89 eV on thick $hbox{SiO}_{2}$ interface layer, although the eWF rolls off with reducing EOT. Excellent transistor characteristics are achieved, with $I_{rm on}$ of $hbox{375} muhbox{A}/muhbox{m}$ at $I_{rm off} = hbox{60 nA}$, for $V_{rm dd} = hbox{1.1} hbox{V}$ .      

A 47 GHz Cross-Coupled VCO Employing High- Island-Gate Varactor for Phase Noise Reduction

A 47 GHz $LC$ cross-coupled voltage controlled oscillator (VCO) employing the high-$Q$ island-gate varactor (IGV) based on a 0.13 $mu{rm m}$ RFCMOS technology is reported in this work. To verify the improvement in the phase noise, two otherwise identical VCOs, each with an IGV and a conventional multi-finger varactor, were fabricated and the phase noise performance was compared. With $V_{DD}$ of 1.2 V and core power consumption of 3.86 mW, the VCOs with the IGV and the multi-finger varactor have a phase noise of $-$95.4 dBc/Hz and $-$91.4 dBc/Hz respectively, at 1 MHz offset, verifying the phase noise reduction with the introduction of the high-$Q$ IGV. The VCO with IGV exhibited an output power of around $-$15 dBm, leading to a FoM of $-$182.9 dBc/Hz and a tuning range of 3.35% (45.69 to 47.22 GHz).      

A 0.1–5 GHz Cryogenic SiGe MMIC LNA

In this letter, the design and measurement of the first SiGe integrated-circuit LNA specifically designed for operation at cryogenic temperatures is presented. At room temperature, the circuit provides greater than 25.8 dB of gain with an average noise temperature $(T_{e})$ of 76 K $(NF=1 {rm dB})$ and $S_{11}$ of $-$ 9 dB for frequencies in the 0.1–5 GHz band. At 15 K, the amplifier has greater than 29.6 dB of gain with an average $T_{e}$ of 4.3 K and $S_{11}$ of $-$14.6 dB for frequencies in the 0.1–5 GHz range. To the authors' knowledge, this is the lowest noise ever reported for a silicon integrated circuit operating in the low microwave range and the first matched wideband cryogenic integrated circuit LNA that covers frequencies as low as 0.1 GHz.      

Bending and Strain Sensitivities in a Helicoidal Long-Period Fiber Gratings

In this letter, we report bending and strain sensitivities of helicoidal long-period fiber gratings fabricated by twisting single-mode fibers during $hbox{CO}_{2}$ laser irradiation. Linear spectral shifts of the resonant wavelengths under the bending and tensile strain were observed with the sensitivities of $-$11.7 nm/m$^{-1}$ and $-$1.1 $hbox{pm}/muvarepsilon$, respectively. The corresponding transmission power variations at the resonance wavelength were 4.1 $hbox{dB/m}^{-1}$ and $2.2times 10^{-4} hbox{dB}/muvarepsilon$, respectively. Detailed measurement techniques and sensor applications are discussed.      

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.      

Temperature Compensated Refractometric Biosensor Exploiting Ring Resonators

A temperature compensated refractometric biosensor in polymeric waveguides was demonstrated by integrating a vertically coupled ring resonator with a laterally coupled ring resonator playing the role of monitoring the temperature. The proposed main sensing part was evaluated by observing the concentration of an aqueous glucose solution, and it was found to work decently around room temperature, yielding the sensitivity of ${sim}$120 pm/(g/dL), and the temperature monitoring part offered a temperature sensitivity of $-$172 pm/ $^{circ}$C. With the help of the temperature compensation, the measurement error of the main sensor resulting from the temperature variation was substantially reduced from 1.33 (g/dL)/$^{circ}hbox{C}$ down to 0.03 (g/dL)/$^{circ}hbox{C}$ .      

Integration and Characteristics of 40-Gb/s Electroabsorption Modulator Integrated Laser Module With a Driver Amplifier and Bias Tees

Integration of a 40-Gb/s electroabsorption modulator integrated distributed feedback (DFB) laser (EML) module with a driver amplifier and bias tee was investigated. For the EML fabrication the selective area growth (SAG) technique was adopted for the first time. It is shown that, with the SAG technique, the 3-dB bandwidth of about 45 GHz was measured in the electrical to optical response, and the return loss (S11) of below $-$10 dB was achieved for up to 50 GHz . To integrate a bias tee within the module, a right-angle bent coplanar waveguide (CPW) was developed. The right-angle bent CPW was characterized with S11 of below $-$ 10 dB for up to 35 GHz and insertion loss (S21) of about $-$1.4 dB for up to 40 GHz . The whole integrated module including the EML, a driver amplifier, and bias tee was characterized under the conditions of an operating temperature of 25 $^{circ}{rm C}$, the modulator bias of 1.4 V, and the DFB laser current of 40 mA. S11 of below $-$10 dB was obtained for up to 14 GHz and the measured electrical-to-optical response has 3-dB bandwidth of about 20 GHz.      

A Digital Intensive Fractional-N PLL and All-Digital Self-Calibration Schemes

A digital intensive PLL featuring a digital filter in parallel with an analog feed-forward path and a digital controlled oscillator (DCO) is presented. Digital loop filter replaces analog passive filter to reduce chip area and associated gate-leakage in advanced process. It also allows the PLL loop gain and DCO gain to be digitally calibrated to within 100 ppm within 50 $mu{hbox{s}}$. Such fine frequency resolution enables the PLL to accurately compensate for the loop parameter variation due to process, voltage and temperature (PVT). The analog feed-forward path is insensitive to quantization error of fractional-N divider and DCO nonlinearity. Direct modulating the DCO frequency and phase through the analog feed-forward path, and compensating the modulating signal digitally for the DCO gain variation are demonstrated. At 3.6 GHz all fractional spurs are under $-$ 75 dBc. The phase noise at 400 kHz and 3 MHz are $-$115.6 dBc/Hz and $-$134.9 dBc/Hz, respectively. The chip is fabricated in a 0.13 $mu$ m CMOS process, and occupies an active area of 0.85 ${hbox{mm}}^{2}$ and draws 40 mA from a 1.5 V supply including all auxiliary circuitry.      

Fabrication and Characterization of Fused Microfiber Resonators

We fabricate a 2.6-mm-diameter loop resonator from a tapered, step-index silica fiber of thickness $sim$ 7.2 $mu$ m. The resonator has a coupling region that is fused with a CO$_{2}$ laser for reducing structural instabilities and improving the overall stability of the device. We experimentally demonstrate optical resonances with a $Q$-factor ${ge}$25 000 at a free-spectral range of 0.19 nm.      

A 5-GHz CMOS Type-II PLL With Low $K_{rm VCO}$ and Extended Fine-Tuning Range

A 5-GHz dual-path integer-$N$ Type-II phase-locked loop (PLL) uses an LC voltage-controlled oscillator and softly switched varactors in an overlapped digitally controlled integral path to allow a large fine-tuning range of approximately 160 MHz while realizing a low susceptibility to noise and spurs by using a low $K_{rm VCO}$ of 3.2 MHz/V. The reference spur level is less than $-$70 dBc with a 1-MHz reference frequency and a total loop-filter capacitance of 26 pF. The measured phase noise is $-$75 and $-$115 dBc/Hz at 10-kHz and 1-MHz offsets, respectively, using a loop bandwidth of approximately 30 kHz. This 0.25-${hbox{mm}}^{2}$ PLL is fabricated in a 90-nm digital CMOS process and consumes 11 mW from a 1.2-V supply.