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  • Publications 2020

Publications 2020

since January 2020

(1) Millimeter-Wave Single-Layer Full-Band WR12 Vertical Waveguide Transition
W. Ahmad, D. Kissinger, H.J. Ng
Proc. IEEE Radio and Wireless Symposium (RWS 2020), 298 (2020)

(2) Frequency Interleaving IF Transmitter and Receiver for 240-GHz Communication in SiGe:C BiCMOS
M.H. Eissa, N. Maletic, L. Lopacinski, A. Malignaggi, G. Panic, R. Kraemer, G. Fischer, D. Kissinger
IEEE Transactions on Microwave Theory and Techniques 68(1), 239 (2020)
DOI: 10.1109/TMTT.2019.2940018, (fast spot)
This work presents fully-integrated modular wideband frequency interleaving (FI) transmitter and receiver for high data rate communication applications. At the transmitter side three independent I/Q baseband channels are up-converted to different intermediate frequencies (IF) and then interleaved. At the receiver side the interleaved signals are down-converted and separated back to each independent channel. Single-ended inputs and outputs are utilized in order to reduce the pin count, for a more practical realization and higher potential toward future system scaling. Special design techniques are followed to minimize cross-talk and inter-modulation products between the channels. All circuits are manufactured and measured in a 130nm SiGe:C BiCMOS technology with fT / fmax = 300 / 500 GHz. The FI transmitter achieves a channel bandwidth of 2.5 GHz with less than 3 dB difference across the different channels till 15 GHz IF. It consumes 560mW from 2.5V and 3.3V supplies, and occupies a silicon area of 1.9mm2. The FI receiver achieves a baseband channel bandwidth of 2.5GHz with a 1 dB difference between the channels till the same IF. It consumes 890mW from 2.5V and 3.3V supplies, and has a chip area of 1.55mm2. The circuits are deployed in a communication experiment, firstly in a back-to-back test with direct cable connection, demonstrating a data rate of 15.6 Gb/s across the three IQ channels with a 16- QAM modulation scheme and worst case transmitter-to-receiver (Tx-to-Rx) error vector magnitude (EVM) of -18.6 dB. Then a wireless experiment is performed with a 240 GHz front-end with on-chip antenna, demonstrating a data rate of 7.8 Gb/s with QPSK modulation and worst case EVM of -8.3 dB across a wireless link of 15 cm. To the best of the authors’ knowledge this is the first work that demonstrates a wireless transmission at sub-THz carrier frequencies utilizing frequency interleaving architectures.

(3) A V-Band Bidirectional Amplifier-Module for Hybrid Phased-Array Systems in BiCMOS Technology
A. Gadallah, M.H. Eissa, D. Kissinger, A. Malignaggi
Proc. IEEE Radio and Wireless Week (RWW 2020), 330 (2020)

(4) Ridge Gap Waveguide Based Liquid Crystal Phase Shifter
M. Nickel, A. Jimenez-Saez, P. Agrawal, A. Gadallah, A. Malignaggi, C. Schuster, R. Reese, H. Tesmer, E. Polat, D. Wang, P. Schumacher, R. Jakoby, D. Kissinger, H. Manue
IEEE Access 8, 77833 (2020)
In this paper, the gap waveguide technology is examined for packaging liquid crystal (LC) in tunable microwave devices. For this purpose, a line based passive phase shifter is designed and implemented in a ridge gap waveguide (RGW) topology and filled with LC serving as a functional material. The inherent direct current (DC) decoupling property of gap waveguides is used to utilize the waveguide surroundings as biasing electrodes for tuning the LC. The bed of nails structure of the RGW exhibits an E-field suppression of 76 dB in simulation, forming a completely shielded device. The phase shifter shows a maximum figure of merit (FoM) of 70°/dB from 20 GHz to 30 GHz with a differential phase shift of 387° at 25 GHz. The insertion loss ranges from 3.5 dB to 5.5 dB depending on the applied biasing voltage of 0V to 60 V.

(5) Modular Baseband Processing for mm-Wave and THz Communication
G. Panic, M.H. Eissa, L. Lopacinski, N. Maletic, R. Kraemer
Proc. 8th Small Systems Simulation Symposium (SSSS 2020), 49 (2020)

(6) A Compact Circular Multipass Cell for Millimeter-Wave/Terahertz Gas Spectroscopy
N. Rothbart, K. Schmalz, H.-W. Hübers
IEEE Transactions on Terahertz Science and Technology 10(1), 9 (2020)
DOI: 10.1109/TTHZ.2019.2950123, (DFG-AGS)
Millimeter-wave/Terahertz (mmW/THz) spectroscopy is a promising tool for gas sensing applications, such as breath analysis or the detection of toxic chemicals, which require compact portable systems. Long gas cells that are needed for high sensitivities are often bulky and limit the portability of the system. We present a compact mmW/THz circular multipass gas cell with an optical path length of 1.9 m and an outer diameter of only 21.5 cm. The beam is refocused at each internal reflection as a consequence of the large divergence of the mmW/THz beams. We determined the losses of the cell to about 3 dB around 250 GHz and demonstrated sensitive gas spectroscopy with a detection limit of 14 ppm/√Hz for acetaldehyde in a mixture with methanol.

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