Microwave Schaltungsdesign

Schaltungsentwurf vollintegrierter analoger Frontends zur Anwendung in THz-Kommunikations- und Radarsystemen

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

Kontakt

PDF

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!

Kontakt

PDF

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

Contact

Please refer to PDF for more details.

PDF

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.

Contact

Link to SOLITONIC project

 

 

PDF

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.

Contact

Link to SOLITONIC project

 

 

PDF

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.

PDF

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

Contact

Link to SOLITONIC project

PDF

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.

PDF

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.

PDF

A key component of transmitters at high frequencies is the power amplifier (PA), which is usually the last stage in the transmitter chain and responsible for the output power. At high frequencies, the generation of RF power is challenging due to technological limitations. Placing several amplifiers in parallel increases the achievable output power. Depending on the needed output power, primarily due to temperature issues, it can be beneficial to realize the parallelization in the package rather than on-chip. In order to parallelize several amplifiers, in the package, power combining and splitting structures are needed. Common ways to fabricate high power packaging (e.g. split block or PCB modules) are often very expensive or limited in performance. In contrast, at IGM, a low-cost RF packaging technology using ultraprecise deposition (UPD) printing to fabricate coplanar waveguides (CPW) and derived structures has recently been developed. UPD uses a high viscosity silver nano-ink that is deposited on RF substrates through a very thin nozzle and can achieve precision comparable to the back-end-of-line in chip fabrication. In this thesis, jointly supervised by ILH and IGM, the existing approach should be expanded to fabricate and measure package-level power combining and splitting structures using the expertise in RF design and measurement at ILH and the technological capabilities and know-how at IGM.

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A key component for transmitter design is the power amplifier (PA) as last stage of a Tx frontend. This PA is responsible for the power generation for long distance communication or radar applications. For high frequency devices the possible output power is limited by the breakdown behavior of the transistors, which is divined by the band gap of the used semiconductor technology. An interesting material for high frequency power amplifier is GaN, due to it´s large breakdown voltage and high fmax. IMS Chips is able to produce GaN Transistor with adjustable threshold voltage. This allows for  different power amplifier topologies. In order to use the GaN technology modeling of the devices is needed, in order to design PA.

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Kontakt

Dieses Bild zeigt Dominik Koch

Dominik Koch

M.Sc.

Gruppenleiter Leistungselektronik / Wissenschaftlicher Mitarbeiter

Dieses Bild zeigt Benjamin Schoch

Benjamin Schoch

M.Sc.

Wissenschaftlicher Mitarbeiter

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