Design and Characterization of a 15 GHz 4-Channel Local Oscillator distribution module for THz Sensing Units
The multidimensional characterization of the radio channel and models derived from it are a core component in the development of radio systems for newly accessible frequency ranges. An important focus of current research is the (sub-)THz frequency range, which promises high data rates and low latency for future mobile communications standards (6G)1. Due to significant changes compared to the familiar sub-6 GHz or mm-wave bands, metrology, i.e., the verification and characterization of measurement equipment, is also an important research topic that must deliver concepts for the calibration and certification of measurement technology in parallel with the actual applications. As part of the DFG-funded research group “METERACOM – Metrology for THz Communication,” the EMS group is developing metrological concepts for the multidimensional characterization of the radio channel.
An important component of this is directional resolution, which is achieved by means of antenna groups and suitable signal processing. For this purpose, the METERACOM project equipped a 4-element linear array for the 300 GHz frequency range with RF components for the up-mixing of 4 independent baseband signals2. To commission this measurement hardware, suitable conditioning/distribution of the local oscillator (LO) in the baseband is now necessary to ensure phase-coherent operation of the array.
Specific task description:
The main objective is the design of a LO distribution PCB module that provides the array frontend with 4 phase-coherent LO (clk) signals in the frequency range from 9 to 15 GHz. The aim is to distribute the LO signal generated by a programmable RF synthesizer3 to four paths, taking into account correct termination and impedance matching, and to amplify it in order to achieve the required input power of 7dBm for the mixers. Due to the frequency range and the resulting market situation for available components, there are two main concepts – (A) active splitter with low consecutive signal amplification or (B) passive splitter with greater consecutive/preliminary amplification – which are suitable for the project. These are analyzed and compared in advance using RF simulators such as ADS or HFSS. After analysis and preliminary review, a decision is made on a concept to be put into practice. To this end, the student develops the circuit using “components off the shelf” (COTS), dimensions impedance-controlled structures based on knowledge of the dielectric properties of the substrate and the circuit parameters of the circuits used, and performs the route and place (layout) using KiCAD or EAGLE software.
Due to their scope and their highly engineering-oriented nature, these topics are most suited for a student assitant or research project position.
Prerequisites §
- Circuit Design: You are able to design analog/RF and digital circuitry (schematic and layout) using KiCad or EAGLE software tools. Through your knowledge of signal integrity and electromagnetic fields, propagation, and compatibility your design becomes robust and reliable.
- RF: You are able to apply simulation tools such as ADS or HFSS within your design workflow.
- Prototyping/ Debugging: You are able to produce a working prototype of your design (mainly soldering, technical commissioning)
- Programming: You have basic programming skills in Python/Numpy for evaluation and visualisation.
- Laboratory work: You can use basic laboratory equipment such as signal generators and signal analyzers, know how to use and connect RF components, are familiar with calibration concepts, and can use Python/SCPI for measurement automation.
- Language: English/German (also in technical discussions).
- Programs targeted: EIT (B/M/D), II (B/M), MNT (M), CSP (M)