Début de stage : Février ou mars 2025

Lieu du stage : LAPLACE et LAAS / ENSEEIHT / Bât. E

Context:
Several applications require the use of very directive antennas. The best candidate to answer
the radiation specifications is the array antenna (figure 1). However, the array antenna needs
to use a feeding network (figure 2) that increases the insertion losses and reduces the aperture
efficiency of antenna.

To avoid the problem of the feeding network and optimize the radiation performances, many
applications (such: SatCom, 5G, satellites, Nanosat, automotive …) start to use the
transmitarrays antenna (TAA). The operating principle of this kind of antenna is illustrated in
the figure 3, [Ref 1-2]. For this transmit array antenna, individual phase control of each unit cell
enables reconfiguration and thus control of the radiation pattern (beam formation and beam
orientation).
In previous design, the PIN diodes has been used to control the phase of each unit cell.
However, the bias circuits made the design complex and increase the losses

The main objective of this internship is to design a reconfigurable unit cell in X-band with an
optical control. Replace the PIN diode by a photodiode, figure 4.

Required work
During this project, the student(s) will practice a research work on a new and attractive project
that permits to acquire a quasi-complete experience in both RF and photonics research and
technical areas.
The different tasks are as follow:
1. Literature review (state of the art).
2. Select the photodiode and design a measurement setup (transmission line kit).
3. Design or optimize a unit cell in X-band with the control circuit.
4. Characterize the unit cell and study the performances (comparative studies with an
electrical control)

Contact :
Hamza KAOUACH:
Olivier Bernal: