Offene studentische Arbeiten
Motivation:
Die stetig wachsende Bedarf an immer höheren Datenraten in drahtlosen Kommunikationssystemen erfordert die Erschließung neuer Frequenzbereiche. Die Entwicklung analoger Tx- / Rx-Frontends im THz-Frequenzbereich (~ 220 – 330 GHz) stellt dabei große Herausforderungen an das Schaltungsdesign der einzelnen Komponenten.
Ziele:
- Entwicklung und Evaluierung verschiedener Schaltungstopologien für Mischer, Frequenzmultiplizierer oder Verstärker im THz-Frequenzbereich (~ 220-330 GHz)
- Circuit Design und Layout der Konzepte in einer III-IV Halbleitertechnologie
Aufgaben:
- Evaluierung vorhandener Entwürfe
- Entwicklung neuer Konzepte
- Circuit-level Simulationen mit ADS
- 3D Feld-Simulationen mit CST/Momentum
- MMIC Layout mit Cadence
- Literaturrecherche
Nowadays at times of 5G, IoT and autonomous driving systems and subsystems are becoming more and more important in the mmW-range. In order to shrink the size of those systems Globalfoundriesdelivers with his 22nm process a cutting-edge technology and is leading in performance in the CMOS domain.
Core of this thesis: DECIDE YOURSELF!
The topic of this thesis is totally up to you. You can design one or more components of a whole Transceiver system. Investigate the technology limits and decide witch topology of a mixer, power amplifier, low-noise amplifier, switch, multiplier is most suitable to achieve the best system performance!
Goals of this work:
- design of at least one transceiver component
- make a system evaluation
- evaluation of different topologies (active and passive)
- investigation of the limits of this technology
- is the system performance reachable?
Your are perfectly suited if:
- you are interested in integrated circuit-design
- you have a good knowledge in the RF/mmWdomain
- you have already experience with developing tools like Cadence or ADS
Charakteristisch für eine konventionelle Mikrostreifenleitung ist u. a. eine homogene GND Metallfläche. Um die elektrischen Eigenschaften einer solchen Leitung zu beeinflussen, können in die ebene GND-Fläche bestimmte Muster in der Metalisierung eingeführt werden. Voruntersuchungen haben gezeigt, dass periodische Schlitze in einem bestimmten Abstand die Leitung auf mehreren Weisen positiv beeinflussen.
Goals of this work:
- wissenschaftliche Analyse bestimmter Muster in der GND-Fläche
- Optimierung bestimmter elektrischer Eigenschaften
- Aufsetzen einer full 3D-EM Simulation (Abb. 3)
- Modellierung einer Mikrostreifenleitung für den Entwurf in ADS
Das Einbringen bestimmter Muster in der GND-Fläche stellt dabei in einerIII-V-Technologie eine große Besonderheit dar!
Motivation:
A novel FMCW radar principle operates without an explicit local oscillator signal in the receiver, but relies on self-mixing of the receiver.
Goals:
Developement of circuit parts for a SiGe based Radar Transceiver MMIC.
Tasks:
a.o.:
- Design and simulation of a selected analog circuits e.g. mixer, amplifier, multiplier
- MMIC layout and verification
Please refer to PDF for more details.
Our research group develops analog frontends for THz wireless communication systems operating in H-band (220-325 GHz).
In scope of the SOLITONIC project, it is required to implement an integrated envelope detection functionality in the power amplifier monolithic integrated circuit in order to enable and investigate analog and digital pre-distortion techniques.
The goal of this thesis is to design a monolithic integrated envelope detector circuit operating at a center frequency of 300 GHz.
You will use the state-of-the-art 35 nm InGaAs HEMT technology from the Fraunhofer Institute of Applied Solid-State Physics, which has cutting-edge high frequency and low noise performance and achieves cutoff frequencies (f_max) of well beyond 1 THz.
The task includes the choice of the most appropriate circuit architecture, linear and non-linear circuit analysis, optimization and the creation of a production-ready MMIC layout. A focus is on high circuit compactness for on-chip co-integration of the envelope detector circuit with the PA stage.
The workload will be adjusted according to which kind of thesis you execute.
Our research group develops analog frontends for THz wireless communication systems operating in H-band (220-325 GHz).
In scope of the SOLITONIC project, several active and passive components need to be designed to provide the pre-distortion functionalities of the monolithic integrated power amplifier circuit.
Active:
-Controllable phase shifter and attenuator
-Active power divider
-Buffer amplifier
Passive:
-2- and 3-way power divider
-2- and 3-way power combiner
-Coupler
The goal of this thesis is to design and optionally layout some of these components operating at a center frequency of 300 GHz. For that, circuit simulations and electro-magnetic simulations need to be conducted.
You will use the state-of-the-art 35 nm InGaAs HEMT technology from the Fraunhofer Institute of Applied Solid-State Physics, which has cutting-edge high frequency and low noise performance and achieves cutoff frequencies (f_max) of well beyond 1 THz.
The workload will be adjusted according to which kind of thesis you execute.
Ultra-wideband power amplifier become more and more
important for high-speed data transmission like it is planned in
6G communication networks.
Thereby, a flat gain shape response of a total system is required
for those highspeed data communication systems.
An imbalance in the gain of e.g., a transmitter leads into
different power densities in different channels, which is
unwanted.
Additionally, the fact that the insertion loss of passive
components in the communication system like in cables, or
transmission lines rise with frequency, affects the gain
response of the total system [Fig. 1].
To overcome now this issue a peaking ultra-wideband amplifier
with increasing gain shape over frequency can be
implemented.
The goal of this amplifier is to compensate the rising losses of
those passives in order so lead into an overall flat gain and
power response of the total communication system.
With different kind of peaking techniques, a gain response of a
peaking amplifier as depicted in Fig. 2 can be reached.
As already excessively investigated for RF and Microwave power amplifiers, load and source pull simulations and measurements prove useful in describing and improving the linearity and output power performance. These investigations can also be done for mixers in order to improve the mixer performance. Usually, the mixer is embedded into amplifying stages, couplers and other functional stages to form complete transceivers. This opens up the degree of freedom for interstage matching and harmonic terminations even in mixers. The goal is to investigate the potential of these technique to enhance mixer performance in millimeter-wave and THz analog transmit and receive frontends.
Our research group develops analog frontends for THz wireless communication
systems operating in H-band (220-325 GHz).
In scope of the SOLITONIC project,
an analog pre-distortion operating at a center frequency of 300 GHz will be developed. One approach for the realization of the analog pre-distortion is to exploit the complementary properties of expanding and compressing amplifier classes. For compressing amplifier classes (class A/AB) we have valid simulation models for the transistors available. Expanding amplifier classes (class B/C) are not modeled accurately, because these nonlinear expanding amplifiers can not be used independently for communication purposes. In order to get insights, we need measurements of the class
B/C biased amplifiers.
The goal of this thesis is to design and create a production-ready layout of a single-
stage class B/C amplifier operating at a center frequency of 300 GHz. For that, circuit simulations and electro-magnetic
simulations need to be conducted. You will use the state-of-the-art 35 nm InGaAs HEMT technology from the Fraunhofer Institute of Applied Solid-State Physics, which has cutting-edge high frequency and low noise performance and achieves cutoff frequencies (f_max) of well beyond 1 THz
In order to achieve Tbit/s communication links, like for the Open6GHub project, broadband transceiver frontends are needed. Bandwidths up to 100 GHz (in the H-Band) are desired. Further more the frontend needs to be able to work with different signal sources and frequency bands at the same time. To design those frontends there are several broadband active and passive components necessary like mixers, amplifiers and couplers. One key component especially for the signal combining is the broadband splitter/combiner. For high data rates and different IF-bands, they have to be ultra broadband. Those couplers can be active and passive components.
The task will be the investigation of different state of the art active power splitter and combiner concepts and the design of those circuits.
A key component for designing transceivers is the mixer. Usually the IF port of a mixer is directly feed off chip into the modem. This leads to some disadvantages like the direct connection to a fixed 50 Ohm load. Therefor the mixers IF port needs to be directly matched to 50 Ohm what can be difficult for a broadband IF signal. Also the optimum load for the mixers IF port usually differs from 50 Ohm, but matching might be difficult using passive components. Another disadvantage of the direct connection to off-chip environment is due to possible power fluctuations, which might be harmful for the mixer. This could be improved by using an additional IF buffer amplifier. This buffer could protect the mixer and pre amplify the IF signal before it is feed into the modem. Another benefit of the buffer is the possibility of matching the IF port to an optimum load according to load-pull theory.
In this work an additional IF buffer amplifier will be designd based on load and source pull simulations in order to improve mixer performance.
In order to achieve Tbit/s communication links, like for the Open6GHub project, broadband transceiver frontends are needed. For bandwidths up to 100 GHz (in the H-Band) are desired. There are several broadband active and passive components necessary like mixers, amplifiers and couplers. Key component especially for the modulating of signals are IQ-mixers, also balanced mixers and amplifiers are important components. In order to design those broadband 90°-Hybrid and 180° coupler are needed. For example in a balanced IQ-mixer several 90°-Hybrids and 180°-couplers are needed. Those couplers can differ strongly depending of the frequency range.
This work will be about basic investigation of coupler fundamental properties in a 35nm InGaAs mHEMT technology. Based on the results several 90°- and 180° Coupler topologies should be designed and compered.
Kontakt
Dominik Koch
M.Sc.Wissenschaftlicher Mitarbeiter
Kevin Muñoz Barón
M.Sc.Wissenschaftlicher Mitarbeiter
Ruben Schnitzler
M.Sc.Wissenschaftlicher Mitarbeiter