Tx Channels Research Articles

A Novel Space–Time Coding Alamouti Waveform Scheme for MIMO-SAR Implementation

This letter presents a novel extended space-time coding waveform scheme for multiple-input-multiple-output synthetic aperture radar implementation. The extensions include the fulfilling of the two Alamouti periods in one transmit duration minimizing the time-variant channel effect and the new form of the basic orthogonal waveforms. The main advantages of the proposed waveform scheme include ghost image prevention, cross-channel interference mutual cancelation, simultaneous transmission via orthogonal Tx channels, free selection of PRF, etc. The proposed techniques are verified by a simulation for the case of point-like targets.

Fiber-optic links based on silicon photonics for high-speed readout of trackers

We propose to use silicon photonics technology to build radiation-hard fiber-optic links for high-bandwidth readout of tracking detectors. The CMOS integrated silicon photonics was developed by Luxtera and commercialized by Molex. The commercial off-the-shelf (COTS) fiber-optic links feature moderate radiation tolerance insufficient for trackers. A transceiver contains four RX and four TX channels operating at 10 Gbps each. The next generation will likely operate at 25 Gbps per channel. The approach uses a standard CMOS process and single-mode fibers, providing low power consumption and good scalability and reliability.

An unbalanced-to-balanced diplexer based on substrate integrated waveguide cavity

A novel unbalanced-to-balanced diplexer based on a dual-mode substrate integrated waveguide SIW cavity is proposed and implemented. The diplexer is realized using one dual-mode cavity and two single-mode cavities. By properly choosing, feeding and coupling the cavity operating at the TE102 or TE201 mode, so as to not only provide capabilities to realize the desired unbalanced-to-balanced transmission within both Rx and Tx channels but also realize good differential-mode channel-to-channel isolation. To the author's knowledge, we present for the first time an unbalanced-to-balanced type diplexer based on the application of SIW. The proposed diplexer was successfully designed, simulated, and fabricated. Good agreement can be observed between simulated and measured performances in our letter. The measured in-band common-mode rejection is better than 33 dB for both channels. A minimum differential-mode isolation of about 50 dB across the Rx band and about 40 dB across the Tx band is also observed in the measurement. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:173-177, 2015.

A novel 3D cavity diplexer with compact size using LTCC technologies for V-band wireless communication systems

In this article, a novel concept of 3D integrated V-band diplexer, which permits the realization of compact size using a dual-mode cavity and four single-mode cavities, has been realized in low-temperature cofired ceramic technologies. The dual-mode cavity resonator acting as one resonator for both Rx and Tx filters is developed to generate two resonant modes TE102 and TE103 at the center frequency of Rx 56.5-58.5 GHz and Tx 64-66 GHz channels, separately. Meanwhile, this dual-mode cavity becomes the interconnect between Rx/Tx channels and help to realize good isolation without using conventional T-junction. In the measurement, each filter designed for Rx and Tx channels exhibits excellent performance. Channel-to-channel isolations better than 35 dB across the Rx band and better than 32.5 dB across the Tx band are also obtained. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:141-145, 2015.

A new high-speed optical transceiver for data transmission at the LHC experiments

We report on results of radiation tests of a new commercial off-the-shelf fiber-optic link as a candidate for the transmission of data from the detector to the counting room for experiments at the Large Hadron Collider (LHC). The device is manufactured by Molex using CMOS integrated silicon photonics developed by Luxtera. A transceiver contains four RX and four TX channels operating at 10 Gbps each, and is packaged in a QSFP+ module. The approach uses a standard CMOS process and single-mode fibers, providing low power consumption and good scalability and reliability. We present performance measurements, radiation tolerance measurements, and plans for deployment in the ATLAS experiment at the LHC.

Extending a DWDM Optical Network Test System to 12 Gbps x4 Channels

A "Development Platform" for prototyping new multi-GHz ATE has recently been introduced (Keezer et al. 2009). The first application was a multi-channel test system for characterizing an optical network switch operating at 2.5 Gbps per channel (Keezer et al. 2009, 2010). Nine transmitter channels (TX) and nine receivers (RX) were used to test the Dense Wavelength Division Multiplexing (DWDM) switching network. This present paper incorporates elements from the prototype designs into full-feature test modules targeting applications between 2.5 Gbps and 24.0 Gbps per channel. Specifically, the optical test system is extended for burst-mode 12 Gbps DWDM packets (more than 4-times the rate of the original system). Using 8 TX channels, an aggregate data rate of 96 Gbps is achieved. Alternatively, some modules can be configured to double the channel-count (up to 18) while operating at the lower 2.5 Gbps rate (45 Gbps aggregate rate). Lower rates permit use of lower-cost optical components. Two new modules are described with testability features such as: (1) support for "loopback" testing of DUT output-to-inputs, (2) DC electrical tests, (3) 2-to-1 multiplexing up to 24 Gbps, (4) ATE self-test/calibration loopback paths. Recently multiple Development Platforms have been constructed that can operate either independently or synchronized using very low-jitter (~1 ps RMS) clock distribution paths.

A 24-Channel, 300 Gb/s, 8.2 pJ/bit, Full-Duplex Fiber-Coupled Optical Transceiver Module Based on a Single “Holey” CMOS IC

We report here on the design, fabrication, and high-speed performance of a compact 48-channel optical transceiver module enabled by a key novel component: a “holey” Optochip. A single CMOS transceiver chip with 24 receiver (RX) and 24 laser diode driver circuits, measuring 5.2 mm × 5.8 mm, becomes a holey Optochip with the fabrication of forty-eight through-substrate optical vias (holes): one for each transmitter (TX) and RX channel. Twenty-four channel, 850-nm VCSEL and photodiode arrays are directly flip-chip soldered to the Optochip with their active devices centered on the optical vias such that optical I/O is accessed through the substrate of the CMOS IC. The holey Optochip approach offers numerous advantages: 1) full compatibility with top emitting/detecting 850-nm VCSELs/PDs that are currently produced in high volumes; 2) close integration of the VCSEL/PD devices with their drive electronics for optimized high-speed performance; 3) a small-footprint, chip-scale package that minimizes CMOS die cost while maximizing transceiver packing density; 4) direct coupling to standard 4 × 12 multimode fiber arrays through a 2-lens optical system; and 5) straightforward scaling to larger 2-D arrays of TX and RX channels. Complete transceiver modules, or holey Optomodules, have been produced by flip-chip soldering assembled Optochips to high-density, high-speed organic carriers. A pluggable connector soldered to the bottom of the Optomodule provides all module electrical I/O. The Optomodule footprint, dictated by the 1-mm connector pitch, is 21 mm × 21 mm. Fully functional holey Optomodules with 24 TX and 24 RX channels operate up to 12.5 Gb/s/ch achieving efficiencies (including both TX and RX) of 8.2 pJ/bit. The aggregate 300-Gb/s bi-directional data rate is the highest ever reported for single-chip transceiver modules.

Hardware for quasi-single-shot multifrequency magnetic induction tomography (MIT): the Graz Mk2 system

Magnetic induction tomography (MIT) has been suggested by several groups for the contact-less mapping of the passive electrical properties of tissues via AC magnetic fields in the frequency range between several tens of kHz and several tens of MHz. Multifrequency MIT as an analog to multifrequency EIT has been tried and first image reconstructions have been demonstrated with phantoms. MIT appears to yield comparable images to EIT but offers the advantage of being non-contacting. In the beta-dispersion range of most tissues the method is challenging because the signals are very small and buried in noise. In order to minimize drifts and systematic errors fast data acquisition is therefore pivotal. This paper presents a method for single-shot MIT which allows us to acquire the data for a multifrequency image with an analog bandwidth of 50 kHz–1.5 MHz which covers a good part of the β-dispersion of many tissues. The transmit (TX) coils are simultaneously driven by individual power amplifiers with a multisinus pattern with up to 3 App. The amplifiers are configured as current sources so as not to perturb the excitation fields by inappropriately terminated coils. The separation of the different TX channels after reception is achieved by splitting up the carrier frequencies into individual subcarriers with a narrow spacing of at most 300 Hz. In this way every TX coil is identifiable by its own subcarrier but the whole excitation band is contained within a few kHz. The real and imaginary parts of the received signals are extracted efficiently with FFT. The system noise and the sources for low-frequency perturbations are analyzed and characterized.

A V-band front-end with 3-D integrated cavity filters/duplexers and antenna in LTCC technologies

This paper presents a compact system-on-package-based front-end solution for 60-GHz-band wireless communication/sensor applications that consists of fully integrated three-dimensional (3-D) cavity filters/duplexers and antenna. The presented concept is applied to the design, fabrication, and testing of V-band (receiver (Rx): 59-61.5 GHz, transmitter (Tx): 61.5-64 GHz) transceiver front-end module using multilayer low-temperature co-fired ceramic technology. Vertically stacked 3-D low-loss cavity bandpass filters are developed for Rx and Tx channels to realize a fully integrated compact duplexer. Each filter exhibits excellent performance (Rx: IL<2.37 dB, 3-dB bandwidth (BW) /spl sim/3.5%, Tx: IL<2.39 dB, 3-dB BW /spl sim/3.33%). The fabrication tolerances contributing to the resonant frequency experimental downshift were investigated and taken into account in the simulations of the rest devices. The developed cavity filters are utilized to realize the compact duplexers by using microstrip T-junctions. This integrated duplexer shows Rx/Tx BW of 4.20% and 2.66% and insertion loss of 2.22 and 2.48 dB, respectively. The different experimental results of the duplexer compared to the individual filters above are attributed to the fabrication tolerance, especially on microstrip T-junctions. The measured channel-to-channel isolation is better than 35.2 dB across the Rx band (56-58.4 GHz) and better than 38.4 dB across the Tx band (59.3-60.9 GHz). The reported fully integrated Rx and Tx filters and the dual-polarized cross-shaped patch antenna functions demonstrate a novel 3-D deployment of embedded components equipped with an air cavity on the top. The excellent overall performance of the full integrated module is verified through the 10-dB BW of 2.4 GHz (/spl sim/4.18%) at 57.45 and 2.3 GHz (/spl sim/3.84%) at 59.85 GHz and the measured isolation better than 49 dB across the Rx band and better than 51.9 dB across the Tx band.