Millimeter-wave Tunable Hybrid-Transformer in 40-nm CMOS for full duplex high speed data communication over a polymer fiber

Extension to Internship + Master thesis is possible
Starting date: July 2016


NXP is involved in building a demonstrator to show the feasibility of > 1Gbs full duplex data communication over a polymer waveguide at 80 GHz. Because of the full duplex operation it is very important to create a high isolation between the co-located transmitter and the receiver in order to minimize desensitization caused by so called “near-end” crosstalk. Since the transmitter and receiver are connected via a combiner to the same “antenna” (feed to the polymer waveguide) the crosstalk is mainly determined by the isolation of this combiner.

The effective isolation between the TX and RX port will strongly depend on the difference in impedance at the antenna and load balance port, and since the antenna impedance can vary due to environmental effects the isolation can get “out of control” (Fig. 1 (a)).Previous work [1, 2] done at TU/e, see Fig. 1 (b), shows that by adding tunable elements to the hybridtransformer the effect of a difference in impedance at the output ports can be compensated and the isolation can be restored. This concept looks very promising for our demonstrator, but the feasibility should be proven based on a real IC-design in 40-nm CMOS and taking into account all relevant boundary conditions set by the overall system.

Research proposal

  • Define the requirements which have to be fulfilled from an overall system point of view to successfully implement a tunable Hybrid-transformer in the system described in the introduction (bandwidth, tuning range, insertion loss, large signal behavior, ..)
  • Design an "ideal" transformer based on simplified models of components in 40-nm CMOS and check the performance against the requirements.
  • Translate the simplified lumped element model into a "physical" 3D electromagnetic simulation model for the "real" transformer and verify if the required performance can still be met.
  • Identify potential performance limiting factors in the design (or technology) and investigate possibilities for improvement.
  • After a joint evaluation of the achieved performance the project strives for a tape-out in 40-nm CMOS technology of the most favorable structure.

The master student will be located most of the time at NXP on the High Tech Campus Eindhoven and will work together with IC designers and a system architect of NXP. Regular coaching meetings will be held with the supervisor from TU/e and NXP. The student will receive a student remuneration from NXP during the project. It is possible to combine the internship and master thesis project with this topic.

Contact NXP: Pieter Lok ; Joost van Beek
Supervisor TU/e: Marion Matters 


[1] Chuang Lu, Marion K. Matters-Kammerer, Abolghasem Zamanifekri, A. Bart. Smolders, Peter G. M. Baltus, A Millimeter-Wave Tunable Hybrid-Transformer-Based Circular Polarization Duplexer With Sequentially-Rotated Antennas, IEEE Transactions on Microwave Theory and Techniques, Year: 2016, Volume: 64, Issue: 1, Pages: 166 - 177.

[2] Chuang Lu, Marion K. Matters-Kammerer, Reza Mahmoudi, Peter G. M. Baltus, A millimeter-wave tunable transformer-based dual-antenna duplexer with 50 dB isolation, Proceedings of the IEEE 2014 Custom Integrated Circuits Conference, Year: 2014, Pages: 1 - 4.