Prediction of loss minima in infra-red optical fibres

Loss minima in two fluoride glass and chalcogenide glass fibres were calculated. The intrinsic losses are predicted to be 1 × 10?3 dB/km at 3.4 ?m for BaF2-GdF3-ZrF4 glass fibre, 1 × 10?2 dB/km at 2.7 ?m for BaF2-CaF2-YF3-AlF3 glass fibre and 1 × 10?2 dB/km at 4.5 ?m for GeS3 glass fibre.     

Fiber-Optic Polarizer Using Resonant Tunneling through a Multilayer Overlay

We demonstrate an in-line fiber-optic polarizer using resonant tunneling through a leaky multilayer overlay for the first time. Polarization extinction ratio (PER) ? 27 dB with an insertion loss (IL) ? 3 dB has been demonstrated experimentally with scope of further improvement. A simple planar waveguide model is developed to analyze the device whose predictions match very well with the experimental results. It is further shown that by properly selecting the device parameters one can achieve PER ? 68 dB with IL ? 0.2 dB for λ = 0.6328 μm and PER ? 80 dB with IL ? 1.2 dB for λ = 1.3 μm.     

Design a novel 5.8 GHz wideband low noise amplifier in CMOS technology for WLAN applications

A novel complementary metal-oxide semiconductor (CMOS) low noise amplifier (LNA) was designed in this paper for wireless local area network (WLAN) applications in the 5.8?GHz ISM band. The LNA presents low voltage and low power dissipation design integrated in TSMC 0.18?µm standard CMOS technology and achieves a gain of 15.2?dB, a noise figure of 2.5?dB and an IIP3 of ?6.5?dBm with input return loss ?38.5?dB, output return loss of ?46.1?dB while dissipating just 4.96 mW from a 1V supply voltage.     

High-isolation single-mode wavelength-division multiplexer/demultiplexer

A single-mode fibre-optic wavelength-division multiplexer/demultiplexer with excellent isolation is reported. The device utilises a fused biconical structure similar to that of 3 dB couplers and exhibits an insertion loss of 0.04 dB and a wavelength isolation of 43 dB at 1.300 ?m and 30 dB at 1.523 ?m.     

A low-voltage ultra-wideband down-conversion mixer with improved power conversion gain

This article presents a wideband mixer using a TSMC 0.18?µm complementary metal-oxide semiconductor technology process for ultra-wideband (UWB) system applications. The measured 3-dB radio frequency (RF) bandwidth is from 3 to 8.4?GHz with an intermediate frequency of 10?MHz. The measurement results of the proposed mixer achieve 8.1?dB average power conversion gain ?5?dBm input third-order intercept point (IIP3) at 7.4?GHz and 12.4–13.3?dB double side band noise figure. The total dc power consumption of this mixer including output buffers is 3.18?mW from a 1?V supply voltage. The output current buffer consumption is about 2.26?mW with an excellent local oscillator-RF isolation of up to 40?dB at 5?GHz. The article presents a mixer topology that is greatly suitable for low-power operation in UWB system applications.     

A 186 to 212?GHz Downconverter in 90?nm CMOS

The design and measurements of a 200?GHz downconverter in 90?nm standard CMOS are presented. A positive conversion gain of +6.6?dB, a noise figure of 29.9?dB and an output bandwidth of 3?GHz are measured for an LO power of ?14.9?dBm. The conversion gain remains within 3?dB for an RF frequency between 186 and 212?GHz. Downconversion of BPSK and QPSK signals is demonstrated with eye diagrams and constellation plots with data rates over 4?Gbit/s. A mathematical analysis is made of the MOSFETs in the triode region and a new small-signal parameter κ is introduced, which enables the design of the mixing transistors for minimum conversion loss.     

A novel design of circularly polarised antenna based on metamaterial

This article presents a novel design of circularly polarised microstrip antenna based on a metamaterial reflection plane and a half-wave antenna. The metamaterial is composed of two pieces of substrates coated on one side with split ring resonators. Both the experimental and simulated results show that good circularly polarised radiation performances are obtained. The 10?dB return-loss impedance bandwidth and 3?dB axial ratio bandwidth of proposed antenna are 12% and 7%, respectively, and the gain of proposed antenna compared with the half-wave antenna is improved from 6?dB to 9?dB in the design frequency range.     

A dual mode 2.4-GHz CMOS low noise amplifier employing body biasing

This paper presents a dual mode CMOS low noise amplifier (LNA) suitable for Worldwide Interoperability for Microwave Access applications, at 2.4?GHz. The design concept is based on body biasing. An off chip Digital to Analog Converter is used to generate the proper body bias voltage to control the LNA gain and linearity. Measurement results show that in the high gain mode, for V _BS?=?0.3?V, the cascode LNA, implemented in a 0.13???m CMOS standard process, exhibits a 14?dB power gain, a 3.6?dB noise figure (NF) and ?4.6?dBm of third order intercept point (IIP3) for a 4?mA current consumption under 1?V supply. Tuning V _BS to ?0.55?V, switches the LNA into the low gain mode. It achieves 8.6?dB power gain, 6.2?dB NF and 6?dBm IIP3 under a constrained power consumption of 1.7?mW.     

Quasiplanar 3 dB hybrid for millimetre-wave integrated circuits

A quasiplanar 3 dB hybrid suitable for integration in millimetre-wave fin-line circuits is presented. The performance of the device is characterised by 0.5 dB insertion loss, less than 0.5 dB imbalance and 20?25 dB isolation over the entire Ka-band (26.5?40 GHz).     

1.5-V CMOS exponential current generator

A new low-voltage CMOS exponential current generator is proposed in this work. MOS transistors in weak-inversion region and a master?Cslave technique for the temperature compensation were used. The circuit was fabricated with standard CMOS 0.35???m process using a single supply voltage of 1.5?V. Experimental results validate the theoretical analysis and verify the effectiveness of the proposed structure. A 40?dB range linearly in dB controlled output current with less than 1.5?dB linearity error was achieved. The structure features ±1 and ±3?dB deviations for ±10% supply voltage and 80°C temperature variations, respectively.     

Low-power digitally-controlled variable gain attenuator and LNA with high gain dynamic range for sub-GHz ISM bands

A low-power Digitally-controlled Variable Gain Attenuator and Low Noise Amplifier are implemented in a 40-GHz f_T 0.25-??m BiCMOS process. They cover the sub-GHz ISM bands for automotive applications such as Remote Keyless Entry. The LNA achieves wideband input matching independent of the variable gain, as well as high reverse isolation, thanks to a partial feedback technique. Its variable gain is based on a resistor-chain gain-control technique, leading to fine gain steps and constant output impedance. This LNA is designed with 15 gain steps of 1?dB. The simulated results for the maximum gain show a Transducer Power Gain of 16.5?dB, a Noise Figure of 2.4?dB and respective input and output IP₃ of ?12.1 and +4.5?dBm, while only drawing 1.45?mA from a 2.7?V power supply. The measurement results are slightly degraded because of wire-bonding couplings in the package. This LNA is preceded by a five coarse steps (about 11?dB each) digitally-programmable attenuator based on a hybrid T and R-2R network. Together with the LNA, more than 50?dB of gain dynamic range is achieved. For high attenuation steps, input IP₃ of more than +18?dBm is reached.     

Fabrication and performance of 1.5?m GaInAsP travelling-wave laser amplifiers with angled facets

A broadband 1.5?m GaInAsP travelling-wave laser ampli-fier has been realised with angled facets instead of anti-reflection coatings. The measured signal gain for the TE mode is 19dB at the wavelength around 1.49?m with a 2dB gain ripple over one free spectral range and a 3dB band-width of 55 nm. The estimated residual modal reflectivity is 0.2%.     

Ultrafast GaAs microwave PIN diode

This letter describes what is believed to be the first successful realisation of GaAs PIN diodes. The vertical structure was grown on an n+ substrate by MOCVD of a 2 ?m, 1015 cm?3 unintentionally doped n? layer followed by a 0.3 ?m, 4×1019 cm?3 Zn doped p+ layer. The isolation and insertion loss of a single shunt-mounted device are typically ?27 dB and 0.7 dB, respectively. The switching speed of the device was measured to be less than 1 ns.     

Microstrip Lowpass Filter with Very SharpTransition Band Using T‐Shaped,Patch, and Stepped Impedance Resonators

A compact microstrip lowpass filter (LPF) with an elliptic function response is proposed. A high equivalent capacitance and inductance between the structures of the resonator result in the sharp transition band of 0.04 GHz from 4 GHz to 4.04 GHz with an attenuation level of ?3 dB and ?20 dB, respectively. To improve the LPF rejection band, multiple open stubs are connected to the proposed resonator. A filter with a 3‐dB cut‐off frequency at 4 GHz is designed, fabricated, and measured, and agreement between the measured and simulated results is achieved. The results show that a stopband bandwidth of 131% with a suppression level better than ?20 dB is obtained while achieving a compact size with a wide stopband.     

Design and implementation of 75~110 GHz elliptical dual balun in 90 nm CMOS for W-Band transceiver

ABSTRACT

We demonstrate an elliptical dual balun structure for 94 GHz image radar transceiver. The results of two prototypes with small chip size of 0.0256 mm² are reported. For the first one (i.e. dual balun 1), the input couple-line width is 4 mm and coupled-line space is 2 µm. That is, the distance between the output couple-lines is 8 mm. For the second one (i.e. dual balun 2), the input couple-line width is 2 mm and coupled-line space is 3 mm. The distance between output couple-lines is also 8 mm. The other geometric parameters of the two dual baluns are the same. In a star double-balanced mixer or a four-way power amplifier, the dual balun is applicable for four-way power splitting. Over the 92 ~ 96 GHz, dual balun 1 attains prominent S₁₁ of ?14.4~ ?16.4 dB, S₂₁ of ?7.61~ ?7.67 dB, S₃₁ of ?8.78~ ?8.93 dB, S₄₁ of ?7.43~ ?7.6 dB, S₅₁ of ?9.68~ ?9.89 dB, amplitude imbalance magnitude (AIM) smaller than 2.39 dB, and phase difference deviation (PDD) smaller than 3.6°. Furthermore, dual balun 2 attains remarkable S₁₁ of ?13.8~ ?14.8 dB, S₂₁ of ?7.8~ ?7.95 dB, S₃₁ of ?8~ ?8.39 dB, S₄₁ of ?7.46~ ?7.72 dB, S₅₁ of ?8.18~ ?8.54 dB, AIM smaller than 0.95 dB, and PDD smaller than 3.8°, close to those of dual balun 1.     

X-band TRAPATT amplifiers

A 2-stage, class-C. X-band pulsed trapatt amplifier has been demonstrated, giving a maximum gain of 9·5 dB over a 1 dB bandwidth of 200 MHz at a centre frequency of 9.4GHz. The trapatt diodes have a silicon p+?n?n+ structure with silver integral heatsinks and gold-button heat reservoirs. Single-stage amplifiers have been operated with input pulse widths of 0·5 ?s and gains of 5 dB, with 11%3 dB bandwidths centred at 9·2 GHz.     

Electrically cascaded surface-acoustic-wave resonator filters

Three nearly identical surface-acoustic-wave resonator filters at ? 35 MHz have been fabricated with aluminium metallisation on yz LiNbO3 substrates. The filters are electrically cascaded to yield a combined frequency response that exhibits 80 dB sidelobe suppression, Q ? 3000, no spurious responses in the range 1?500 MHz and an insertion loss in a 50 ? system of only 13 dB.     

Optimised structure for preparing long ultra-low-loss single-mode fibres

An optimised structure has been evolved for producing long lengths of ultra-low-loss single-mode fibre. Attenuation figures of 0.6 dB/km at 1.3 ?m and 0.34 dB/km at 1.6 ?m have been achieved in fibres up to 17.1 km in length. The absorption due to OH impurity has been reduced to <3 dB/km at 1.39 ?m.     

Monolithic integrated waveguide photodetector

An InGaAs photodetector for detection in the 1.0?1.5?m wavelength range has been integrated at the end of and above a ridge waveguide in InP. The waveguides were in n?-InP/n+-InP and had an average propagation loss of 3dB/cm at 1.15?m. The reflection losses were 3dB and the coupling loss was 2dB. The photodetector was an InGaAs photoconductor lattice-matched to InP and exhibited a bias-dependent optical gain of up to 2.5 with a unity-gain quantum efficiency of 49% at 1.15?m. 25% of the guided light was absorbed by the photoconductor. The speed of the photoconductor was found to be bias-dependent, varying from 10 ns to 150 ns rise/fall times.     

Narrow, high-NA GaAs/GaAlAs optical waveguides with losses below 0.7±0.1 dB cm-1

Losses as low 0.65 dB cm-1 (3 ?m width) and 0.3 dB cm-1 (8 ?m width) have been measured (? = 1.15 ?m) in high-confinement (NA ? 0.45) GaAs/GaAlAs optical waveguides grown by MOCVD. The Fabry?Perot loss measurement technique used in deduced to be accurate to ±0.1 dB cm-1. These are the lowest losses reported for gudies of high electro-optic merit in III-V materials.