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Signal flow graph (SFG) representation of small-signal responses of nonlinear microwave circuits around a large-signal operating point is developed using the X-parameters. It is shown that, unlike the SFGs for linear circuits, negative-frequency nodes need to be included explicitly. The development elucidates the circuit-operational meaning of the elusive T-type small-signal X-parameters, which represent interaction between positive- and negative-frequency components. As an example, such an SFG is used to derive a closed-form expression of the output power of an amplifier as a function of the load reflection coefficient. It is then used to plot approximate load-pull power contours. The result is consistent with the expressions of the optimum load reflection coefficient derived by Root et al. (EuMIC 2017) and of power contours derived by Peláez-Pérez et al. (TMTT 2013). SFGs provide an alternative systematic means to derive closed-form expressions in terms of X-parameters and to gain illuminating insights into the workings of weakly nonlinear circuits.

Background ABL1 is primarily known as a leukemia-related oncogene due to translocation, but about 2.2% of ABL1 mutations have been identified in bladder cancer, and high expression in solid cancer has also been detected. Methods Here, we used the NCBI database, UCSC genome browser gateway and Tandem repeat finder program to investigate the structural characterization of the ABL1 breakpoint region and to identify the variable number of tandem repeats (VNTR). To investigate the relationship between ABL1-MS1 and bladder cancer, a case-controlled study was conducted in 207 controls and 197 bladder cancer patients. We also examined the level of transcription of the reporter gene driven by the ABL1 promoter to determine if the VNTR region affects gene expression. Results In our study, one VNTR was identified in the breakpoint region, the intron 1 region of ABL1, and was named ABL1-MS1. In the control group, only two common alleles (TR13, TR15) were detected, but an additional two rare alleles (TR14, TR16) were detected in bladder cancer. A statistically significant association was identified between the rare ABL1-MS1 allele and bladder cancer risk: P = 0.013. Investigating the level of transcription of the reporter gene driven by the ABL1 promoter, VNTR showed inhibition of ABL1 expression in non-cancer cells 293 T, but not in bladder cancer cells. In addition, ABL1-MS1 was accurately passed on to offspring according to Mendelian inheritance through meiosis. Conclusions Therefore, the ABL1-MS1 region can affect ABL1 expression of bladder cancer. This study provides that ABL1-MS1 can be used as a DNA fingerprinting marker. In addition, rare allele detection can predict susceptibility to bladder cancer.

A 272-GHz CMOS receiver (RX) for IEEE 802.15.3d, capable of an analog BPSK/QPSK demodulation based on a Costas loop, is presented. A QPSK demodulation is realized with the non-linear operation of a phase detector at the BPSK-demodulation Costas loop. An 8-Gbaud BPSK and a 4-Gbaud QPSK demodulation at the carrier frequency of 272.16 GHz (channel 58 of IEEE 802.15.3d) are achieved.

This paper describes a single axis MEMS accelerometer with the wide detection range of acceleration from micro-G level to 20 G $(\mathrm{G}=9.8\ \mathrm{m}/\mathrm{s}^{2})$ . We propose the MEMS accelerometer with two proof masses on a single chip of $4 \times 4\ \text{mm}^{2}$ in area. One proof mass is for over micro-G level sensing and the other is for below 20 G sensing. The experimental results of the fabricated device show that the Brownian noise $B_{\mathrm{N}}$ and the sensitivity $S$ of the proof mass for over micro-G level are $0.18 \mu \mathrm{G}/\sqrt{\text{Hz}}$ and 5.0 pF/G, respectively and these of it for below 20 G are $0.81 \mu \mathrm{G}/\sqrt{\text{Hz}}$ and $3.7 \times 10^{-2}\ \text{pF}/\mathrm{G}$ , respectively. It is confirmed that the proposed device could realize the wide detection range of acceleration from micro-G level to 20 G. (130)

This paper describes a novel capacitive-detection electrode for a single gold proof-mass three-axis MEMS (microelectromechanical systems) accelerometer. We propose a 3-D capacitive-detection electrode (3-DCE) for a high and uniform sensitivity to sense micro-G (G=9.Sm/s2) level. Based on the analysis in terms of the sensitivity and the Brownian noise B N , we design and fabricate the device with 3-DCE by the multi-metal layer technology for a post-CMOS process. The experimental results show that the obtained B N is 0.16 µG/√Hz and the sensitivities of X-, Y-, and Z-axis are 162, 210, and 341 fF /G, respectively.

We report a detailed study of magnetization reversal in Fe/GaMnAs bilayers carried out by magnetotransport measurements. Specifically, we have used planar Hall resistance (PHR), which is highly sensitive to the direction of magnetization, and is therefore ideally suited for tracking magnetization as it reorients between successive easy axes in the two magnetic layers during reversal. These reorientations take place separately in the two magnetic layers, resulting in a series of different magnetization alignments (parallel or orthogonal) during reversal, providing a series of stable PHR states. Our results indicate that the magnetic anisotropy of the structure is dominated by cubic symmetry of both layers, showing two in-plane easy axes, but with significantly different energy barriers between the easy orientations. Importantly, a careful analysis of the PHR results has also revealed the presence of strong ferromagnetic interlayer exchange coupling (IEC) between the two magnetic layers, indicating that although magnetization reorients separately in each layer, this process is not independent, since the behavior of one layer is influenced by its adjacent magnetic neighbor. The ability to design and realize multiple PHR states, as observed in this investigation, shows promise for engineering Fe/GaMnAs bilayer structures for multinary magnetic memory devices and related multinary logic elements.

A single-chip CMOS transceiver (TRX) capable of wireless data rates up to 80 Gb/s using part of frequencies (252–279 GHz) covered by IEEE Std 802.15.3d is presented. The TRX chip operates in either transmitter (TX) or receiver (RX) mode at frequencies comparable to ${f_{\mathrm {max}}}$ of the NMOSFET. The TX part adopts mixer-last architecture with four-way power combining using a ring circuit called a double-rat-race. The RX part adopts fundamental-mixer-first direct-conversion architecture. In the RX mode, the TX serves as an LO multiplier chain, which conventionally accounted for a significant part of the RX die area. The double-rat-race, having an improved design than the original one, integrates the TX and RX and also rejects unwanted harmonics generated by the frequency-doubler-based upconversion mixer. Low-loss, low-characteristic-impedance transmission lines are used extensively to combat losses. The TRX was fabricated using a 40-nm CMOS process. The saturated output power of the TX is −1.6 dBm at 265.68 GHz. The mean single-sideband noise figure (SSB NF) of the RX is 22.9 dB. The TX mode and the RX mode consume dc power of 890 and 897 mW, respectively. A wireless data rate of 80 Gb/s between a pair of TRX chips is demonstrated with 16QAM over a distance of 3 cm.

THz wireless communications offer very high data rates but tend to be power hungry. This paper demonstrates a technique for drastically reducing receiver-side power consumption for near-field links using 300-GHz CMOS transmitter (TX) and receiver (RX). Since a significant part of RX-side power consumption is accounted for by THz LO signal generation used for downconversion, the RX obviates the need by letting the TX send out not only a signal sideband but also an LO signal, which is a by-product of upconversion and usually is suppressed. The RX then performs self-heterodyne mixing for signal downconversion. The TX and RX can operate in this low-power "full-(pseudo-)carrier transmission/reception mode" and in the ordinary "suppressed-(pseudo-)carrier TX/RX mode." In the low-power mode, the RX achieved a data rate of 17.64 Gb/s with 64-QAM over 1 cm at 6 mW dc power consumption at 295.92 GHz. The dc power consumption in normal mode was 645 mW at comparable data rates.

This paper presents a millimeter-wave (mmW) sub-sampling PLL in 40 nm CMOS. Sub-sampling PLL reduces the in-band phase noise due to the charge pump lower than the ordinary N2× when frequency is multiplied by N. Two sub-sampling phase detectors (SSPD) and charge pumps (SSCP) are employed to cancel mixing products due to sub-sampling around the VCO output tone and to enhance loop gain. The out-of-band phase noise, dictated by the VCO phase noise, is reduced by employing a VCO consisting of transmission-line resonators, large MOSFET switches, and inverse-class-F output matching. The proposed PLL, operating at 45 GHz, achieves −40-dBc integrated phase noise (0.1 kHz–40 MHz), 3.9-dBm output power, and 2.1% DC-to-RF efficiency.

Hydrodynamic phonon transport was recently predicted as an important regime for phonon transport in graphitic materials. Many of the past studies on hydrodynamic phonon transport have focused on the cases where the hydrodynamic regime is significantly stronger than other regimes such that hydrodynamic features can be clearly observed. However, this often requires stringent conditions of temperature and sample size. In many cases, the transport cannot be characterized by a single regime, but the features of all three regimes---ballistic, hydrodynamic, and diffusive regimes---exist to some extent. Here we assess the extent of three regimes by comparing momentum destruction rates by three different mechanisms, each of which represents a different regime: diffuse boundary scattering without internal phonon scattering (ballistic regime), diffuse boundary scattering combined with normal scattering (hydrodynamic regime), and umklapp scattering (diffusive regime). We solve the Peierls-Boltzmann equation with an ab initio full scattering matrix using a deviational Monte Carlo method. We sample distribution functions of ballistic and scattered particles separately, and thereby compare the momentum destruction rates by the three different mechanisms. Using this framework, we discuss a well-known phenomenon of ballistic-to-hydrodynamic crossover, called the phonon Knudsen minimum.

Magnetization reversal in a GaMnAs trilayer system consisting of two GaMnAs layers separated by a Be-doped GaAs spacer was investigated by magnetotransport measurements. The rotation of magnetization in the two GaMnAs layers is observed as two abrupt independent transitions in planar Hall resistance (PHR). Interestingly, one GaMnAs layer manifests a positive change in PHR, while the other layer shows a negative change for the same rotation of magnetization. Such opposite behavior of the two layers indicates that anisotropic magnetoresistance (AMR) has opposite signs in the two GaMnAs layers. Owing to this opposite behavior of AMR, we are able to identify the sequence of magnetic alignments in the two GaMnAs layers during magnetization reversal. The PHR signal can then be decomposed into two independent contributions, which reveal that the magnetic anisotropy of the GaMnAs layer with negative AMR is predominantly cubic, while it is predominantly uniaxial in the layer with positive AMR. This investigation suggests the ability of engineering the sign of AMR in GaMnAs multilayers, thus making it possible to obtain structures with multi-valued PHR, that can be used as multinary magnetic memory devices.

We discuss the use of planar Hall effect (PHE) in a ferromagnetic GaMnAs film with two in-plane easy axes as a means for achieving novel logic functionalities. We show that the switching of magnetization between the easy axes in a GaMnAs film depends strongly on the magnitude of the current flowing through the film due to thermal effects that modify its magnetic anisotropy. Planar Hall resistance in a GaMnAs film with two in-plane easy axes shows well-defined maxima and minima that can serve as two binary logic states. By choosing appropriate magnitudes of the input current for the GaMnAs Hall device, magnetic logic functions can then be achieved. Specifically, non-volatile logic functionalities such as AND, OR, NAND, and NOR gates can be obtained in such a device by selecting appropriate initial conditions. These results, involving a simple PHE device, hold promise for realizing programmable logic elements in magnetic electronics.

This paper presents a low-power RF-CMOS-transceiver IC-module with small antennas on a printed circuit board (PCB). Active mixer-first architecture is employed on a receiver for achieving both acceptable sensitivity and lower power. We also show strategies for lowering power consumption of the transmitter and the phase locked loop (PLL): a high-gain inverter-based resonant-driver and a current-reuse voltage controlled oscillator (VCO). Power saving of the RF circuits is achieved with low supply-voltage design under 0.5V by exploiting forward body bias technique. The use of 5.5-GHz band and a J-shaped folded monopole antennas (JFMA) on the PCB enable to reduce the module footprint, and the module size of 0.78 cc is realized. The proposed transceiver circuit is fabricated in 65 nm CMOS process technology and is mounted on the PCB. 5.5-GHz RF-transceiver operation is succeeded with small power consumption of 1.56 mW under 0.5-V power supply. Output signal-power of the transmitter is −23.2 dBm, and receiver sensitivity is −61.2 dBm.

We report a systemeatic investigation of magnetic anisotropy of quaternary GaMnAsP ferromagnetic semiconductor films by magneto-transport. Hall measurements showed a transition of the easy magnetization direction from in-plane to out-of plane with incorporation of the P into the GaMnAs films. Quantitative information on magnetic anisotropy of the films is obtained by fitting the angular dependence of Hall resistance data to magnetic free energy using the coherent rotation model. Values of magnetic anisotropy parameters show that in-plane anisotropy decreases and out-of-plane anisotropy increases with increasing P content in these films. The out-of-plane magnetic anisotropy in GaMnAsP layers is further enhanced by low temperature annealing. By optimizing the growth and annealing conditions, we were able to obtain a Curie temperature of 125 K in such quaternary films, with strong out-of-plane anisotropy. This study showed that the magnetic anisotropy of the GaMnAsP films can be controlled by adjusting the concentration of the P, and by appropriate post-growth annealing.

An 8 channel output switching driver has been implemented for integrated micro-electro-mechanical systems (MEMS) device control using the 0.18 µm CMOS process technology. The driver can output 20 V switching signals for 1 nF capacitive loads with a 3.3 V power supply. The switching time is less than 100 µs. To obtain a high output voltage that exceeds the transistors’ and capacitors’ breakdown voltages, a new charge pump and a discharge circuit, using optimal transistor-well-biasing techniques for triple-well-structured n-MOS transistors, were investigated, and the circuit parameters were also optimized to obtain high-speed switching.

An inductorless phase-locked loop with subharmonic pulse injection locking was realized (PLL area: 0.11 mm2) by adopting 90 nm Si CMOS technology. The proposed circuit is configured with two cascaded PLLs; one of them is a reference PLL that generates reference signals to the other one from low-frequency external reference signals. The other is a main PLL that generates high-frequency output signals. A high-frequency half-integral subharmonic locking technique was used to decrease the phase noise characteristics. For a 50 MHz input reference signal, without injection locking, the 1 MHz offset phase noise was −88 dBc/Hz at a PLL output frequency of 7.2 GHz (= 144 × 50 MHz); with injection locking, the noise was −101 dBc/Hz (spur level: −31 dBc; power consumption from a 1.0 V power supply: 25 mW).

This paper proposes an ultra-low-power 5.5GHz PLL which employs a divide-by-4 injection-locked frequency divider (ILFD) and linearity-compensated varactor for low supply voltage operation. The digital calibration circuit is introduced to control the ILFD frequency automatically. The proposed varactor, which applies a forward-body-bias (FBB) technique, is employed for linear-frequency-tuning under the power supply of 0.5 V. The proposed PLL was fabricated in 65 nm CMOS. With a 34.3-MHz reference, it shows a 1-MHz-offset phase noise of -106 dBc/Hz, a reference spur level lower than -65 dBc, and the total power consumption of 950μW at 5.5 GHz.

We report magnetoresistance data in magnetic semiconductor multilayers, which exhibit a clear step-wise behavior as a function of external field. We attribute this highly non-trivial step-wise behavior to next-nearest-neighbor interlayer exchange coupling. Our microscopic calculation suggests that this next-nearest-neighbor coupling can be as large as 24% of the nearest-neighbor coupling. It is argued that such unusually long-range interaction is made possible by the quasi-one-dimensional nature of the system and by the long Fermi wavelength characteristic of magnetic semiconductors.

A wide-frequency-range phase-locked loop (PLL) with subharmonic injection locking is proposed. The PLL is equipped with a wide tunable ring-type voltage-controlled oscillator (ring VCO), frequency dividers, and a doubler in order to the widen injection-locked tuning range (ILTR). In addition, high-frequency injection signals are used to improve phase noise, which is supposed to be generated by a reference PLL. The proposed circuit is fabricated by using a 65 nm Si complementary metal oxide semiconductor (CMOS) process. The measured frequency tuning range is from 1.2 to 17.6 GHz with a frequency doubler and dividers. The phase noise at 14.4 GHz (=32×450 MHz) with injection locking was -109 dBc/Hz, which shows a 21-dB reduction compared with that in the case without injection locking.