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A dual mode InGaP/GaAs heterojunction bipolar transistor (HBT) power amplifier (PA) using a parallel power-combining transformer (PCT) is presented herein. A low loss transformer is implemented on a printed circuit board (PCB) to improve the passive efficiency of a PCT. Dual-mode operation is applied to reduce the current consumption at a low power level. In the low-power (LP) mode, one of the individual amplifiers is turned off to reduce the current consumption. Additionally, a third-order intermodulation distortion (IMD3) cancellation method using a PCT combiner is proposed to improve linearity performance. Nonlinear IMD3 components from each amplifier cancel each other out through magnetic coupling in the secondary winding of the PCT. The implemented PA achieves a saturated output power of 33.8 dBm and a peak power-added efficiency (PAE) of 54.5% at 0.91 GHz with a 5-V power supply. An average output power of 25.2 dBm with an adjacent channel leakage ratio (ACLR) of −42 dBc is delivered when the PA is tested with an orthogonal frequency division multiplexing (OFDM) 64-quadrature amplitude modulated (64-QAM) signal with a bandwidth of 10 MHz and peak-to-average power ratio (PAPR) of 7.8 dB. When compared with the high-power (HP) mode operation, the LP mode operation could save 48% of the current consumption at an average output power of 10.4 dBm.

A 28 GHz watt-level CMOS SPDT switch with integrated electro-static discharge protection is designed and fabricated in a 65 nm CMOS process for a fifth-generation mobile communication. The measured insertion losses of the SPDT are 2.2 dB and 2.6 dB for transmit and receive modes, respectively. The fabricated SPDT switch shows output P1dB of >30 dBm for transmit mode and input P1dB of 4.3 dBm for receive mode.

The effects of non-idealities including clock jitter, rise/fall-time mismatch of a pulse, and pulse-amplitude-level non-linearity on conventional delta-sigma-only and Manchester/delta-sigma-modulated microwave signals are studied. According to the experimental and simulation results, the Manchester/delta-sigma scheme is more vulnerable to jitter than the conventional delta-sigma scheme due to the higher number of pulse transitions by Manchester codes. It is found that, however, because of the repetitive (or multi-pulse) nature, the Manchester/delta-sigma system shows better signal quality performance against a rise and fall time asymmetry. This is mainly because the Manchester pulse waveform is more similar to a return-to-zero format where every encoded bit has both rising and falling edges and is therefore immune to the waveform asymmetry.

This paper presents a miniaturized 28-GHz FEM implemented in 0.15-µm InGaAs/GaAs E-mode pHEMT process. It is designed for use with 28-GHz switching beamforming systems. In order to miniaturize the system, the RF FEM is mounted on the printed circuit board in the form of individual PA, switch, and LNA chips, and development has been made to facilitate the mounting of mobile terminals. The results of the FEM transmitter verification including the implemented filter on the PCB have a gain of 17.9 dB, an output P1 dB of 24.2 dBm and an EVM of -30 dB at 20 dBm output. As a result of the receiver verification, the gain is around 20 dB, the input P1 dB is -30 dBm, and the EVM performance of -30 dB is tested at -10 dBm output.

In this paper, we propose a low noise amplifier (LNA) using a g m -boosting technique with improved stability using transformers in the millimeter-wave (mm-Wave) band. The transformer composed of three inductors improves not only stability, but also gain and low-noise performance of the LNA. The conditions for stability shows that the proposed structure can guarantee good stability over a high frequency range. The chip was fabricated using the TSMC 65-nm CMOS process and it has an active chip area of 0.11 µm2. The fabricated LNA has a gain of 18.33 dB and a noise figure (NF) of 3.25–4.2 dB. The stability factor µ values are 9.7 and 5.2 at the source and load sides of the LNA, respectively. The 3-dB bandwidth of the LNA is 24.9–32.5 GHz and the chip consumes 17.1-mA current from a 1.2-V supply.

A 1.8V MIPI RF front-end (RFFE) circuit for a slave with a 1.0V supply is designed using a CMOS 65 nm process as a control block for a millimeter-wave beamforming array. It is consisted of a MIPI RFFE slave logic, power-on-reset (PoR), SCLK receiver, and SDATA transceiver to support the MIPI RFFE master-slave interface with MIPI RFFE bus. According to simulation results, the designed MIPI RFFE interface circuit provides rise and fall time of less than 3.3 ns with a 26 pF load (one master-eight slave configuration) at the transmission rate of 26 MHz, satisfying the requirement of 6.5 ns in the MIPI RFFE specification version 1.10.

This paper presents a 6-bit 28GHz phase shifter in 65nm CMOS technology. The phase shifter is composed of switching-type phase shifters to achieve low power consumption, low insertion loss, and bidirectionality. The relative phase shift varies from 0° to 354.375° with a step of 5.625°. The result of EM simulation shows that the phase shifter has the insertion loss less than 8.63dB over a frequency range of the 26.5 to 29.5GHz. The return loss is smaller than −10.5dB and the RMS phase error is 3.11°. The core size of the phase shifter is $\mathbf{0.38 \times 0.98 mm^2}$

28 GHz SPDT switch has been designed and fabricated in 65 nm CMOS with deep N-well as a building block for beamforming-based 5th generation mobile communication systems. The measured insertion loss is 1.8 dB at 28 GHz, and IIP3 is measured as 11.75 dBm. The input and output return losses are $ and $ , respectively.

This article describes the design of a low-power 60-GHz OOK transmitter. A simple OOK structure is adopted for a low-power and stable operation. The power consumption is reduced by implementing a LC-VCO that operates at a low-voltage. In addition, a switching modulator in the transmitter consumes less power due to no power consumption at the low-state of a high-speed data signal. The transmitter, implemented in a 65-nm CMOS technology, has an output power of −2 dBm, on/off isolation over 40 dB, and tuning range of 64.8–67.7GHz. It is possible to communicate wirelessly within 5cm while consuming only 13.3 mW. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1977–1980, 2015

In this letter, we present a linear InGaP/GaAs HBT power amplifier (PA) with parallel-combined transistors for small-cell applications. Ballast resistors with bypass resistors and capacitors are employed in parallel-combined transistors. When the resistors and capacitors are set to appropriate values, IMD3 components of the parallel-combined transistors are found to be out of phase with each other by 180° and are canceled out at the output. The experimental results show that the proposed HBT PA with parallel-combined transistors produces a saturated output power of 33.5 dBm at 0.88 GHz, with a power-added efficiency (PAE) of 46.1% at a 5-V supply voltage. To validate the effectiveness of the proposed HBT PA for linearity improvement, the implemented PA is also tested with a long-term evolution (LTE) signal (8.1-dB PAPR with 10-MHz bandwidth). The proposed PA achieves an adjacent channel leakage ratio (ACLR) below −45 dBc at an average power of 25.6 dBm with a PAE of 18.8% without applying predistortion.

We propose a millimeter-wave (mm-wave) InGaAs enhancement-mode (E-mode) 0.15-um pHEMT low-noise amplifier (LNA). The LNA achieves 21.9-dB gain with simulation results of 2.19-dB noise figure (NF) and 9.9-dBm P1dB using 3-V power supply as it consumes 9 mA. The bandwidth of the LNA is 17 GHz (from 18.9 GHz to 35.9 GHz) and the fractional bandwidth (FBW) is 62 %.

We present a fully integrated 2×2 MIMO CMOS LTE RF transceiver along with multi-band InGaP/GaAs HBT power amplifiers for LTE-A small cell (femtocell) base stations. The transceiver features highly integrated LNAs and drive amplifiers with 24 individual RF I/O pins. The multi-band PAs achieves ACLR 38% at 33dBm by employing a third-order intermodulation distortion (IMD3) canceling techniques. The presented SiP composed of proposed radio and PAs shows plenty of margins in radio conformal test of femtocell base station using a commercial modem.

We present a 28-GHz low-noise amplifier (LNA) using 0.15-um InGaAs pHEMT enhancement-mode (E-mode) technology. The 28-GHz LNA exhibits a gain of 22.2 dB and a 3-dB bandwidth of 14.1 GHz (22.7–36.8 GHz) under 3-V supply with 38.5-mA current consumption. The simulation results of the LNA show a noise figure (NF) of 2.13 dB and a P1dB of 10.8 dBm. The chip size is 1488 um × 796 um.

A semilinear LC-voltage-controlled oscillator (VCO) topology is proposed. To exploit a linear frequency tuning, the LC-VCO adopts the variable capacitance block of the varactor devices and the PMOS transistors. This block has the capacitance characteristics which are approximately inversely proportional to the square of the VCO control voltage. The proposed LC-VCO is implemented in a 130-nm CMOS technology. The measurement results show a semilinear frequency range of 503–873 MHz and a phase noise of −128 dBc/Hz at 1 MHz offset frequency. Power consumption is about 2 mA from a 1.2 V supply. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1972–1975, 2013

A highly linear HBT power amplifier (PA) for LTE-A small-cell base-stations is presented. By separating a bias point of the PA sub-cells and combining these outputs with out-of phasing, the third-order intermodulation distortion (IMD) can be reduced. By the simulation results, the third-order IMDs are approximately −50 dBc and −43 dBc with and without the separate biasing at an output power of 29 dBm, respectively. The designed HBT PA has a gain of 31 dB, a P1dB of 35 dBm, and a PAE of 38.1% under 5 V supply voltage.

A 2.6–3.4 GHz low-voltage voltage-controlled oscillator (VCO) with a boosted transconductance is presented. The proposed VCO operates with less current dissipation for oscillation start-up, being enabled to supply voltage reduction. The phase noise of the proposed VCO is improved by not entering in deep triode region of MOSFETs. Implemented in a 65-nm CMOS, the measurements results show 800 MHz of tuning range, consuming 1.56 mW at 0.6 V supply. The measured phase noise is −116 dBc/Hz at 1 MHz offset from a 3.3-GHz carrier. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1671–1674, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26898

This paper describes a transmitter integrated circuit (IC) for 5.8-GHz dedicated short-range communication applications. It consists of a baseband variable-gain amplifier (VGA) and an amplitude-shift-keying (ASK) modulator with an output amplifier. The VGA has exponential gain control characteristics. The proposed temperature- independent exponential gain control is realized with a voltage-to-current converter and n-p-n bipolar transistors. The VGA is powered by 3.3 V with 5 mA. The ASK modulator utilizes the Gilbert topology and consumes 32 mA of current with 3.3-V supply. The conversion gain (in decibels) of the transmitter IC is varied linearly from + 5.3 dB to - 17.7 dB with respect to the control voltage from 0.5 V to 2.5 V. It achieves gain errors of less than plusmn1.2 dB over the 23 dB gain range, an output P1 dB of 3.5 dBm at the maximum gain of 5.3 dB, and an adjacent channel power lower than -45 dBc . It occupies an area of 1770 mum times 1150 mum including the bondpads.

A CMOS wideband cascaded variable gain amplifier (VGA) with a temperature-independent exponential gain control characteristic is presented in this paper. The exponential gain control function is realized using parasitic bipolar transistors and a control signal converter. The bandwidth is extended using an inductive peaking technique for high-frequency operations. The gain of the VGA varies from -38.8 to 55.3 dB in relation to the control voltage that varies from 0 to 1.8 V. The bandwidth of the proposed VGA is approximately 900 MHz with a gain control range of 94.1 dB. The proposed VGA includes a dc offset cancellation loop to avoid amplification of the dc offset. The VGA is powered by 1.8 V with 11.4 mA. The VGA chip including bondpads occupies an area of 850 mum times 490 mum.

A CMOS wideband variable gain amplifier (VGA) with an exponential gain control characteristic is presented. The exponential gain control function is realized by changing the tail currents a differential gain stage. The bandwidth is extended by using an inductive peaking technique. The gain (in dB) of the VGA is varied linearly from −41 dB to 31 dB with respect to a control voltage from 1.38 V to 1.1 V. The bandwidth of the proposed VGA is larger than 1 GHz with a gain control range of 72 dB. A DC offset cancellation loop is included so as to avoid amplification of the DC offset. The VGA is powered by 1.8 V with 13.5 mA. The VGA chip occupies an area of 220 μm × 620 μm. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 812–817, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22278

A low-power 50-GHz LC-VCO has been presented. Throughout EM analysis, an inductor having a quality factor of 14.3 was implemented with a microstrip line. The analyzed characteristics of a MOS varactor limit the LC tank performance due to its low quality factor. In order to overcome the LC tank performance and operate at low-power consumption, the negative transconductance stage was evaluated in various ways and found at the condition of the optimized MOSFET size and bias point. The proposed VCO was implemented in a 65-nm CMOS technology. The measurement results show a frequency range of 48.61 GHz ∼ 50.84 GHz and an output power of −10 dBm. The required VCO current is about 4.7 mA from a 0.7 V supply.

This paper describes the design of a mm-Wave oscillator with a high-speed amplitude modulation. The oscillator can be adjusted the output voltage level according to the highspeed data signal. Additionally, it can be conducted at a low-power for wireless communications by carrying out the oscillation and modulation at the same time. We have verified that the oscillator have tuning range of 52.3–53.5 GHz, phase noise of below −100 dBc/Hz at 1 MHz offset, and two different amplitude levels by the simulation while consuming only 9.3 mW.

The MIPI RFFE slave interface circuit including Power-on-Reset (PoR), SCLK receiver and SDATA bidirectional transceiver has been implemented with a CMOS 250 nm process. Simulation results show that the designed circuit has SDATA output transition time (for rise and fall) of shorter than 3.3 ns at a full-speed rate of 26 MHz, which satisfies the timing requirement (< 6.5 ns) by the specification of MD?I RFFE version 1.10. The target load capacitance that the designed MIPI RFFE slave interface circuit drives is 26 pF for the configuration of one master and eight slaves.

This paper presents a wideband variable gain amplifier (VGA) fabricated using the 0.18-μm CMOS process. An exponential CMOS triode transconductor scheme is proposed to achieve highly linear-in-dB characteristics of a VGA for ultra-wideband (UWB) systems. The proposed VGA achieves a linear-in-dB controllable gain range of 28.4 dB (7 to −21.4 dB) with a bandwidth of 1200 MHz, while drawing only 2.7 mA from a 1.8-V power supply. Measurements show a linear gain range with a linearity error of less than ±0.5 dB. P1dB varies from −8.5 to −6 dBm. The chip occupies an area of 0.2 × 0.2 mm2, excluding bond-pads. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 997–1000, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21546

A digital 5-bit phase shifter at Ku-band is presented, which is implemented with 0.18-mum RFCMOS technology. n-MOSFET switches and top metal microstrip lines with a first-metal ground allow the phase shifter to have small insertion losses. The proposed 90deg phase shifter utilizing a parallel resonator exhibits broad-band characteristics. All of the circuit components are derived to obtain a minimum phase variation at the operation frequency band. A bridged-T type phase shifter is also analyzed in view of parallel resonance using an ideal equivalent-circuit model. The conditions of the circuit elements are derived in an analytic form, which are used to obtain the broad-band phase characteristics. The fabricated 5-bit phase shifter demonstrates an overall rms phase error less than 12deg from 9 to 15 GHz. Insertion losses of 14.5 dB plusmn 0.5 dB and return losses less than 14 dB are obtained for 32 states at 12 GHz. The proposed 90deg phase shifter has performed a phase shift of 92.3degplusmn3.2deg over 9-15 GHz

Detailed flow of a shrouded tail rotor in hover is studied by using a compressible inviscid flow solver on unstructured meshes. The numerical method is based on a cell-centered finite-volume discretization and an implicit Gauss-Seidel time integration. Numerical simulation is made for a single blade attached to the center body and guide by the duct by imposing a periodic boundary condition between adjacent rotor blades. The results show that the performance of an isolated rotor without shroud compares well with experiment. In case of a shrouded rotor, correction of the collective pitch angle is made such that the overall performance matches with experiment to account for the uncertainties of the experimental model configuration. Details of the flow field compare well with the experiment confirming the validity of the present method.

Background: The purpose of this study was to evaluated results of arthroscopic treatment of the traumatic recurrent unidirectional posterior subluxation. Materials and Methods: We treated twenty-seven patients who had traumatic recurrent unidirectional posterior subluxation of the shoulder by arthroscopic labral repair and posterior capsular shift and prospectively evaluated for a mean of thirty-nine months (range,24 to 85 months). Patients who had posteroinferior instability, multidirectional instability, atraumatic onset, or revision cases were excluded. There were twenty-five male and two female patients with the mean age of twenty-one years (range, 14 to 33 years). All patients were involved in sports activity. All had a significant traumatic event prior to the onset of the instability. Stability, motion, three objective measurement (UCLA, ASES, and Rowe scores) and two subjective measurements (pain and function visual analogue scale) were evaluated. Results: The most common finding in magnetic resonance image-arthrogram was separation of the posteroinferior labrum without displacement in 9 patients, In arthroscopic examination, all patients had one or more lesions in the posterior inferior labrum and capsule. The most common finding was incomplete stripping of the posterior inferior labrum (18 patients). The posteroinferior capsule subjectively appeared to be stretched in twenty-two patients. At follow-up, all patients had improved shoulder function and scores(p