Multi-channel Transceiver Research Articles

크로스 아이 재밍을 위한 멀티밴드 다중채널 송수신기의 정밀 가변 위상 및 진폭 매칭 구조 설계

크로스 아이 재밍을 위한 멀티밴드 다중채널 송수신기의 정밀 가변 위상 및 진폭 매칭 구조 설계

Non-Uniform MIMO Array Design for Radar Systems Using Multi-Channel Transceivers

Multiple-input multiple-output (MIMO) technology has recently attracted attention with regard to improving the angular resolution of small antennas such as automotive radars. If appropriately placed, the co-located transmit and receive arrays can make a large virtual aperture. This paper proposes a new method for designing arrays by adopting a structure with minimum redundancy. The proposed structure can significantly increase the virtual array aperture while keeping the transmit and receive antennas at the same size. We describe the application of the proposed method to subarray-type antennas using multi-channel transceivers, which is essential for arranging RF hardware in a small antenna operating at high frequency. Further, we present an analysis of the final beam pattern and discuss its benefits and limitations.

Hairpin RF resonators for MR imaging transceiver arrays with high inter-channel isolation and B1 efficiency at ultrahigh field 7 T

Electromagnetic decoupling among a close-fitting or high-density transceiver RF array elements is required to maintain the integrity of the magnetic flux density from individual channel for enhanced performance in detection sensitivity and parallel imaging. High-impedance RF coils have demonstrated to be a prominent design method to circumvent these coupling issues. Yet, inherent characteristics of these coils have ramification on the B1 field efficiency and SNR. In this work, we propose a hairpin high impedance RF resonator design for highly decoupled multichannel transceiver arrays at ultrahigh magnetic fields. Due to the high impedance property of the hairpin resonators, the proposed transceiver array can provide high decoupling performance without using any dedicated decoupling circuit among the resonant elements. Because of elimination of lumped inductors in the resonator circuit, higher B1 field efficiency in imaging subjects can be expected. In order to validate the feasibility of the proposed hairpin RF coils, systematical studies on decoupling performance, field distribution, and SNR are performed, and the results are compared with those obtained from existing high-impedance RF coil, e.g., “self-decoupled RF coil”. To further investigate its performance, an 8-channel head coil array using the proposed hairpin resonators loaded with a cylindrical phantom is designed, demonstrating a 19 % increase of the B1+ field intensity compared to the self-decoupled coils at 7 T. Furthermore, the characteristics of the hairpin RF coils are evaluated using a more realistic human head voxel model numerically. The proposed hairpin RF coil provides excellent decoupling performance and superior RF magnetic field efficiency compared to the “self-decoupled” high impedance coils. Bench test of a pair of fabricated hairpin coils prove to be in good accordance with numerical results.

A Compact 112-Gbaud PAM-4 Silicon Photonics Transceiver for Short-Reach Interconnects

For next generation highly integrated transceivers, silicon photonics (SiP) has attracted widespread interest in using mature CMOS production processes to manufacture high-yield, low-cost photonic integrated circuits (PIC) with the potential for integration with CMOS electronics. SiP now routinely integrate GeSi electroabsorption modulators (EAM) and GeSi waveguide photodiodes which have high responsivity and possess 3-dB electro-optic bandwidth of over 65 GHz. Their ultra-compact dimensions make it possible for multi-channel transceivers to be realized on a small chip area. In this paper, we demonstrate the high-speed capability of these devices incorporated with optimized digital signal processing (DSP) for 100 Gbaud+ PAM-4 signaling. Using integrated GeSi-EAM and GeSi-photodiode fabricated at a commercial foundry, we carried out intensity modulation and direct detection (IM-DD) transmission experiments in C-band using PAM-4, for both back-to-back and SSMF transmission at 1 km and 1.5 km. Under a 6-dB system bandwidth of ∼43GHz we attained, with the help of DSP equalization, a record 112 Gbaud (224 Gb/s), 108 Gbaud (216 Gb/s) and 100 Gbaud (200 Gb/s) are achieved over back-to-back, 1 km and 1.5 km SSMF transmission respectively, with a bit-error-rate (BER) below the hard-decision forward-error-correction (HD-FEC) threshold of 3.8E-3.

The Impact of Personal Protective Equipment on Speech Discrimination and Verbal Communication in the Operating Room and the Role of Audio Communication Devices.

Recent work has highlighted communication difficulties when wearing personal protective equipment (PPE) in the clinical setting, but currently, there are little objective data on its effects. We assessed the impact of PPE on verbal communication in a simulated operating room and evaluated use of an audio communication device. Frontline health professionals across specialties including surgery, anesthetics, and nursing undertook speech discrimination testing with and without standardized levels of PPE in a simulated operating room environment. Background noise (30- and 70-a-weighted decibel multitalker babble) at 2 distances (2 and 4 m) were selected representative of operating room environments. Bamford-Kowal-Bench (BKB) scoring (192 sentences per participant) was performed. A Digital Multichannel Transceiver System (DMTS) was evaluated. We assessed the effects of PPE use, distance, and use of the DMTS with pairwise comparisons, using a Bonferroni correction, and assessed participant experience via Likert scales. Thirty-one healthcare professionals were tested. Without PPE in 70-a-weighted decibel "babble," median BKB sentence scores were 90% and 76% at 2 and 4 m (adjusted P < 0.0005). The median BKB sentence scores dropped to 8% and 4% at 2 and 4 m in PPE (adjusted P < 0.0005). Improved speech discrimination was achieved with DMTS use to 70% and 76% at 2 and 4 m. Personal protective equipment led to a statistically significant reduction in BKB scores across all conditions compared with baseline. Overall participant confidence in PPE clinical communication was low. Addition of PPE dramatically impairs speech discrimination and communication in high levels of background noise characteristic of clinical environments, which can be significantly improved using DMTS. Measures should be taken by teams through both through reduction of background noise and consideration of assistive technologies maximizing patient safety. This may be further rehearsed in a simulation environment.

A GMSK/PAM4 Multichannel Magnetic Human Body Communication Transceiver

This letter presents a dual-mode multichannel transceiver implemented with low path loss offered by magnetic human body communication (mHBC) toward ultraefficient body-area networking. Two spectral-efficient modulation schemes: 1) Gaussian minimum-shift keying (GMSK) and 2) 4-level pulse-amplitude modulation (PAM4), are used to reduce interference on adjacent channels. A power oscillator is used to efficiently generate both GMSK- and PAM4-modulated magnetic fields while multichannel selection is implemented by on-chip capacitor tuning and an analog PLL, enabling 5 and 10 Mb/s data for GMSK and PAM4, respectively. The transmitter achieves an efficiency of 15.5 and 19.4 pJ/bit, while the receiver consumes 4.6 and 2.7 pJ/bit for GMSK and PAM4, respectively.

A Digitally Controlled Multichannel Spectrally Efficient Low-Power Transceiver for Ultra-Wideband Cognitive Radio Applications

A multichannel transceiver design with low hardware complexity, flexibility and efficient spectrum use intended for Impulse Radio (IR) Ultra-Wideband (UWB) apertures, is proposed in this paper. The transceiver supports 14 channels and is implemented in TSMC CMOS process. The transmitter adopts a symmetrical triangular narrow pulse generator, a multiband LC-VCO, a mixer and a Variable-Gain Amplifier. A digital control of transmitter output power and carrier frequency is achieved by a current-steering Digital-to-Analog Converter (CS-DAC). The receiver follows the noncoherent Energy Detection (ED) scheme including Low-Noise Amplifier (LNA) which takes the benefits of the body biasing technique to further reduce power consumption, squarer and comparator. The LNA achieves high gain of up to 30[Formula: see text]dB allowing to enhance the receiver sensitivity which is [Formula: see text]83.7[Formula: see text]dBm at 25[Formula: see text]Mbps. The transmitter provides output pulses with a width of 3[Formula: see text]ns, a pulse repetition rate of 20[Formula: see text]ns and a maximum Power Spectral Density (PSD) of [Formula: see text]42[Formula: see text]dBm/MHz. The power consumptions of transmitter and receiver are 35.6[Formula: see text]pJ/bit and 0.207[Formula: see text]nJ/bit at 25[Formula: see text]Mbps, respectively. Maximizing utilization of the scarce wireless spectrum, enhancing spectral flexibility and efficiency and reducing power consumption are the main contributions brought by this work, enabling this transceiver to be able to deal with the current debate on producing single multifunctional Cognitive Radio (CR) UWB systems.

47.5 GHz Membrane-III-V-on-Si Directly Modulated Laser for Sub-pJ/bit 100-Gbps Transmission

Near-future upgrades of intra data center networks and high-performance computing systems would require optical interconnects capable of operating at beyond 100 Gbps/lane. In order for this evolution to be achieved in a sustainable way, high-speed yet energy-efficient transceivers are in need. Towards this direction we have previously demonstrated directly-modulated lasers (DMLs) capable of operating at 50 Gbps/lane with sub-pJ/bit efficiencies based on our novel membrane-III-V-on-Si technology. However, there exists an inherent tradeoff between modulation speed and power consumption due to the carrier-photon dynamics in DMLs. In this work, we alleviate this tradeoff by introducing photon–photon resonance dynamics in our energy-efficient membrane DMLs-on-Si design and demonstrate a device with a maximum 3-dB bandwidth of 47.5 GHz. This denotes a bandwidth increase of more than 2x times compared to our previous membrane DMLs-on-Si. Moreover, the DML is capable of delivering 60-GBaud PAM-4 signals under Ethernet’s KP4-FEC threshold (net data rate of 113.42 Gbps) over 2-km of standard single-mode fiber transmission. DC energy-efficiencies of 0.17 pJ/bit at 25 °C and 0.34 pJ/bit at 50 °C have been achieved for the &gt; 100-Gbps signals. Deploying such DMLs in an integrated multichannel transceiver should ensure a smooth evolution towards Terabit-class Ethernet links and on-board optics subsystems.

Research of Tile Type Transceiver Module Integrating with Two-Dimensional Sum Difference Network

Transceiver module and two-dimensional sum difference network are important components of phased array antenna. In this paper, multilayer printed board is used to integrate millimeter wave multi-channel transceiver circuit and sum difference network. The interconnection between them is realized through RF coaxial vertical transition. At the same time, the heat dissipation design and inter channel shielding design of the module are carried out. The RF and low frequency required by the module are completed through the wiring between and within the dielectric plate layers. Finally, 128 arrays are fabricated and verified by multi-channel passive test. The results show that the type transceiver module integrating with two-dimensional sum difference network has good performance, and 128 channels have excellent amplitude and phase characteristics. The integration technology has the characteristics of lightweight, miniaturization, high integration and low manufacturing cost. It can be widely used in miniaturized phased array antennas.

Tranceiver Multi Channels Untuk Kontrol Gerak dan Monitoring Kondisi Pada Robot Manual Mini Industri

Robotic technology that is developing rapidly triggers robotics developers to improve their abilities, especially in the field of robot control and monitoring. Today, robots are indeed present in human life in various forms. One type of robot that is often developed by robotics developers is the Industrial Mini Manual Robot. An industrial mini manual robot is a transporter robot that is equipped with a gripper and is controlled manually by the user through a joystick controller both wired and wireless. The manual robot with cable joystick control is very inefficient in its use so research on wireless joysticks is carried out. However, the current wireless joystick still uses the single-channel method, thereby eliminating multitasking capabilities such as those of the wired joystick robot. In this research, the design of multichannel transceivers for control and monitoring so that the robot has the ability to multitasking and the movement of the robot is not disturbed by wires. Multichannel transceivers use different frequency channels to transmit data. The command data and monitoring data can be transmitted simultaneously. This multi-channel transceiver has an average pairing time of 23.59 ms, a range of 116 meters in each channel and large power consumption of 59 mA.

CMCVT: A Concurrent Multi-Channel Virtual Transceiver

State-of-the-art wireless Gateways (GW) used in Internet of Things (IoT) offer a single channel radio link, which limits the capabilities of the IoT network controlled by the GW, as the GW can only use a single channel at a time to communicate with the end-device(s). The quality of service (e.g., aggregate throughput, latency) offered by a single channel GW could be substantially improved by employing a multi-channel transceiver, which is capable of transmitting/receiving data on different radio channels simultaneously, particularly for larger wireless networks. However, current solutions available in both research and commercial communities only offer multi-channel receiver capabilities, and do not incorporate the multi-channel transmitter part. In addition, in terms of implementation, these multi-channel receivers duplicate single-channel hardware functionality. In this paper, for the first time, a novel concurrent multi-channel virtual transceiver is introduced. The virtual transceiver offers multi-channel capabilities and uses the same single-hardware hardware implementation for the Physical (PHY) layer by employing the virtualization technique. This new virtual transceiver concept is demonstrated for an IEEE 802.15.4 based 8 × 8 channel transceiver, implemented on an Field Programmable Gate Array (FPGA) of a modern Software Defined Radio and is compared with the existing duplication approach. The duplication approach consumes 9008 LUTs, and 12120 FFs, whereas the proposed approach occupies only 2959 LUTs and 2105 FFs, saving 67.15% LUTs and 82.63% FFs in comparison with the duplication approach. The experimental results reveal that the virtual transceiver provides the same performance (e.g., receiver sensitivity of −98.5dBm) as the transceiver achieved by duplicating the PHY layers but consumes much less hardware resources.

Computational Analysis of a Dual Loop Dipole Antenna and Its Interleaving Array for Improving Transceiver ∣B1∣-field for MRI

This article intends to present the electromagnetic (EM) insight of the operation of a double loop shaped dual loop dipole (DLD) antenna as a single-channel transceiver coil and in an array configuration of multi-channel transceiver coil, designed to provide high signal-to-noise ratio (SNR) by using numerical simulations for 300 MHz magnetic resonance imaging (MRI). Thus, this section includes the comparison of DLD antenna and commonly used loop coils through EM simulations. The use of a DLD antenna is proposed to address the length issue that traditional straight dipole have by making a spiral type in a loop style, while having the same effective physical length of the straight dipole. The magnetic flux density (∣B1∣)-fields of the DLD antenna and the traditional loop coil are compared by field maps acquired by EM simulations. In addition, the DLD antenna has been extended to a 7-channels array, for which the magnetic field coupling between each coil is analyzed and presented through the noise correlation matrix. The use of the DLD antenna exhibits higher ∣B1∣-field intensity while keeping the similar uniformity than a surface loop coil. We use the DLD antenna 7-channel array to observe its utility as multi-channel with short distance overlap between elements; each element is approximately 37 mm away from neighboring element. Transceiver array arrangements also show improved coil performance, especially the interleaving configuration with loop coil indicates lowered mutual inductance coupling at calculated noise correlation matrix. The proposed DLD antenna is expected to induce rapid imaging and high ∣B1∣-field, when expanded to multi-channel planar or volume configuration since it can maximize the number of configuring coil elements within limited imaging area leading effective parallel imaging and deeper penetration depth due to the traveling wave.

Design of a Multiple-beam Cassegrain Antenna with Quasi-optical Isolator at 200 GHz for Target Tracking

This letter proposes a multiple-beam Cassegrain antenna with quasi-optical isolator at 200 GHz for target tracking. The proposed antenna is designed with a special topology, in which a multichannel transceiver feed integrated with a quasi-optical isolator is designed and placed in the back of the main reflector, aiming to isolate the transmitting and receiving channels, and to avoid the aperture blockage. Four receiving feeds are laterally defocused to produce offset beams and each of them is received and sampled individually without comparators, which simplifies the structure and provides flexibility for signal processing. An optimization is performed to achieve the best compromise design considering the conflicts induced by its special structure. The fabricated antenna is measured and the results demonstrate an excellent radiation performance of the proposed antenna. Four well-performed offset beams are obtained as expected and the antenna works stably within a bandwidth of 10 GHz. The measured 3 dB beamwidths vary around 0.6° and the sidelobe levels are lower than −12.5 dB for all the beams. The superiorities of the proposed antenna show its potential application in high-performance tracking and imaging systems.

A 76-GHz to 81-GHz, 0.6° RMS Phase Error Multichannel Transmitter With a Novel Phase Detector and Compensation Technique

A multichannel transceiver operating in 76–81 GHz with precisely phase-controlled transmitter for the automotive radar application is presented. To achieve high phase accuracy of transmit signal, a novel phase detector using third-order distortion is proposed to compensate the phase control error. To avoid the insensitivity region on specific phase condition, the frequency-shifted method applying the propagation delay difference between transmit and reference signal path is also presented. The multichannel transmitter using proposed detector achieves less than 0.6° root-mean-square (RMS) phase error in 76-GHz to 81-GHz frequency range, over −40 °C–125 °C ambient temperature condition. Since the proposed phase detector does not use the other TX as reference, it is suitable for extending the number of channels. This transceiver, including the proposed phase detector is implemented in 65-nm CMOS technology. The phase detector consumes 1.8 mW per channel and occupies 0.15 mm2 per channel.

Photonics-assisted direction-of-arrival estimation of electromagnetic interference for GSM-R system in high-speed railways

In the field of high-speed railways (HSRs), electromagnetic interference (EMI) to the wireless train-ground communication system (e.g., the GSM-R system for train scheduling and dispatching) severely reduces the operational efficiency and even results in accidents. The direction-of-arrival (DoA) estimation of EMI is crucial for detection and removal. A photonics-assisted system is proposed to estimate the DoA of EMI for the GSM-R system along the HSRs in a remote and real-time mode. The proposed scheme is featured by simultaneous photonics-assisted detection and location (DoA estimation) of the EMI, with the advantages of strong EMI immunity, low loss transmission, and remote distribution. Here, an integrated optical multichannel transceiver operating as the photonic front end is used to acquire multiple delayed replicas of the electromagnetic signals, and then, a multiple signal classification algorithm is used to estimate their DoAs at the center station. In the indoor experiments, the DoAs ranging from −60 deg to +60 deg are successfully estimated with errors less than 1.2 deg in a 10-km radio-over-fiber link. In the field trials, the GSM-R signal accompanied by a suspected EMI is detected with DoA errors less than 1.8 deg.

Cardiorenal sodium MRI at 7.0 Tesla using a 4/4 channel 1 H/23 Na radiofrequency antenna array.

Cardiorenal syndrome describes disorders of the heart and the kidneys in which a dysfunction of 1 organ induces a dysfunction in the other. This work describes the design, evaluation, and application of a 4/4-channel hydrogen-1/sodium (1 H/23 Na) RF array tailored for cardiorenal MRI at 7.0 Tesla (T) for a better physiometabolic understanding of cardiorenal syndrome. The dual-frequency RF array is composed of a planar posterior section and a modestly curved anterior section, each section consisting of 2 loop elements tailored for 23 Na MR and 2 loopole-type elements customized for 1 H MR. Numerical electromagnetic field and specific absorption rate simulations were carried out. Transmission field ( ) uniformity was optimized and benchmarked against electromagnetic field simulations. An in vivo feasibility study was performed. The proposed array exhibits sufficient RF characteristics, homogeneity, and penetration depth to perform 23 Na MRI of the heart and kidney at 7.0 T. The mean field for sodium in the heart is 7.7 ± 0.8 µT/√kW and in the kidney is 6.9 ± 2.3 µT/√kW. The suitability of the RF array for 23 Na MRI was demonstrated in healthy subjects (acquisition time for 23 Na MRI: 18 min; nominal isotropic spatial resolution: 5 mm [kidney] and 6 mm [heart]). This work provides encouragement for further explorations into densely packed multichannel transceiver arrays tailored for 23 Na MRI of the heart and kidney. Equipped with this technology, the ability to probe sodium concentration in the heart and kidney in vivo using 23 Na MRI stands to make a critical contribution to deciphering the complex interactions between both organs.

Phase retrieval for non-quadrature radio frequency excitation and its preliminary application in MR-EPT

Non-quadrature radio frequency (RF) excitation has been widely studied in the fields of RF shimming, local SAR estimation, and MR-EPT with the use of multi-channel transceiver arrays. These studies generally require the retrieval of the complex transmit field (), which can be accomplished by acquiring its magnitude and phase in different steps. Magnitude of the transmit field is acquired with the conventional methods which give accurate results for both quadrature and non-quadrature excitations. On the other hand, there is no straightforward method to acquire the absolute phase of the transmit field and generally approximations in MRI experiments are made in order to get it. However, many of these approximations fail in non-quadrature excitation and/or in ultra high fields. In this study, we propose a simple method to acquire the absolute transmit phase in non-quadrature excitation with an eight channel transceiver TEM array for 3 T. The proposed method requires the application of a single additional quadrature drive in order to get the receive phases of the individual channels of the transceiver coil. These receive phases are then subtracted from the transceive phase of the non-quadrature drive experiment to acquire its transmit phase. The developed ideas are tested in the framework of simulations and MRI experiments with the use of four different non-quadrature drive configurations. It has been observed that the simulated and experimentally acquired transmit phase distributions tend to have a strong consensus which supports the validity of the proposed method. Finally, the estimated transmit phase distribution of non-quadrature drive is used in the standard MR-EPT study to get the conductivity reconstructions in order for the validation of its eligibility in MR-EPT studies.

Tile Type Multi-Channel Transceiver Module Applied for Phased Array Antenna

In order to reduce the volume and weight of phase array antenna in RF frequency, an integrated technology of multi-channel transceiver circuit and power division network in microwave is proposed for the tile type TR module. The component is integrated in a same dielectric substrate, the mounting interface of chips and power division network are on the same layer. Finally, a 8 × 8 array has been manufactured and tested to validate its function. The results show the integrated technology has good performance. It is very good to satisfy the miniaturization and lightweight of the T/R module in the active phased array antenna.

A Wearable Transcranial Doppler Ultrasound Phased Array System.

Practical deficiencies related to conventional transcranial Doppler (TCD) sonography have restricted its use and applicability. This work seeks to mitigate several such constraints through the development of a wearable, electronically steered TCD velocimetry system, which enables noninvasive measurement of cerebral blood flow velocity (CBFV) for monitoring applications with limited operator interaction. A highly-compact, discrete prototype system was designed and experimentally validated through flow phantom and preliminary human subject testing. The prototype system incorporates a custom two-dimensional transducer array and multi-channel transceiver electronics, thereby facilitating acoustic beamformation via phased array operation. Electronic steering of acoustic energy enables algorithmic system controls to map Doppler power throughout the tissue volume of interest and localize regions of maximal flow. Multi-focal reception permits dynamic vessel position tracking and simultaneous flow velocimetry over the time-course of monitoring. Experimental flow phantom testing yielded high correlation with concurrent flowmeter recordings across the expected range of physiological flow velocities. Doppler power mapping has been validated in both flow phantom and preliminary human subject testing, resulting in average vessel location mapping times <14 s. Dynamic vessel tracking has been realized in both flow phantom and preliminary human subject testing. A wearable prototype CBFV measurement system capable of autonomous vessel search and tracking has been presented. Although flow phantom and preliminary human validation show promise, further human subject testing is necessary to compare velocimetry data against existing commercial TCD systems. Additional human subject testing must also verify acceptable vessel search and tracking performance under a variety of subject populations and motion dynamics-such as head movement and ambulation.

Design and Implementation of a High-Coupling and Multichannel Optical Transceiver With a Novel Packaging Structure

Short-reach optical interconnection mainly focuses on the power consumption, the cost, and the volume. According to these requirements, the design and implementation of a multichannel transceiver are presented in this paper. In this paper, a high-coupling method without the 90° beam deflection is proposed so as to reduce the total power consumption to 0.9 W. Moreover, only the mature and low-cost packaging methods such as wire bonding and flip chip are adopted to satisfy the requirement of the optical coupling, which reduces the cost. Finally, the designed transceiver retains a small size of $28\times 16 \,\, \times $ 3 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . To ensure normal function of the transceiver, the organic substrate is carefully designed, and the post-design simulation is conducted to characterize the electrical performance. At last, the test results show that the optical transceiver with this novel packaging structure is able to transmit the data at 10 Gb/s per channel successfully.