Reconfigurable Wireless Components Using Field Programmable Microwave substrate – RWC_FPMS

WP1:
The work is mainly carried out for this axis by Ontario Tech and Xlim. In order to optimize the behavior of the unit cell of the FPMS, a Matlab code has been implemented to generate an FPMS (matrix of reconfigurable cells) of all sizes and with a number of ports to be defined via a graphical interface. . This code is linked to the circuit model (ADS) of
the unit unit initially designed upstream of the project. The association
equivalent electrical model / Matlab code allows the design of microwave components based on optimization algorithms (topological gradient, genetic algorithms,
...) or even the repair of defects (inactive elementary cells) to reconfigure the
smart material.
WP2:
Most of the work on this axis is carried out by Ontario Tech and the IETR. The design of new elementary cell designs has been initiated allowing operation in
X band (10-12GHz). With these X-band cells, a global FPMS was simulated allowing the
design of straight or angled guides or even reconfigurable power dividers.

Another X-band cell was also used for the design of a leaky wave antenna
reconfigurable with beam depointing and experimental validation has just been carried out
demonstrating the operation of this type of antenna. It is important to note that these
work was carried out between OntarioTech and IETR during a stay in Canada by D. René — Loxq
(IETR doctoral student).
WP3:
The IETR is currently working on the design of inhomogeneous lenses using the cells
elementary with variable dielectric constant. This required the design of a new
cell thus operating around 15GHz. Carleton University is working on the design of leaky wave antennas
reconfigurable allowing the beam to be deflected in multiple directions for
applications around 28GHz.

Several convincing results have already been obtained since the start of the project in connection with the division of the project into work packages:

WP1:
The design of optimization software (Matlab / ADS) to optimize the circuits (guides, filters, etc.) produced using the FPMS. This work was carried out in particular by XLIM

WP2
- The design and manufacturing of reconfigurable X-band leaky waves antennas by the IETR and Ontario Tech. The measurements of a first prototype have just been carried out and confirm the simulations. This prototype required the design of a new unit cell in these frequency bands, a cell which could subsequently be coupled to the optimization algorithm developed within the framework of WP1.

WP3:

- The design of leaky wave antennas that can be reconfigured in millimeter wave band for applications in particular related to 5G. A prototype has been produced by Carleton University and the first measurements have just been made validating the principle of reconfigurability of the radiation pattern.

- The design and production of reconfigurable filters based on the first reconfigurable FPMS in UHF band (Ontario Tech).

- The implementation (simulations) of reconfigurable inhomogeneous lenses at 15GHz. These simulations carried out by the IETR will soon be validated via the measurement of a prototype making it possible to obtain a reconfigurable radiation pattern antenna (beam scanning and beam shaping).

Work will continue in particular concerning the optimization of new cells and the associated reconfigurable substrates (FPMS) in order as planned in the project to increase th working frequency. These developments will be done through multilayer PCB technologies but also LTCC.
Regarding the manufacturing of new prototypes, these will concern both reconfigurable circuits (filters, power dividers) and antennas (leaky waves, reconfigurable lenses) in order to validate the implemented designs.

Several communications in international congresses have highlighted the results obtained from the antennas developed by Carleton University.
Similarly, Ontario Tech has submitted an article in an international journal concerning reconfigurable filters and the IETR is preparing to submit a publication in an international journal concerning the Leaky Wave antenna developed in X-band. All of these publications are set out in the interim report (18 months).

Modern wireless communication systems require high frequency components that can be reconfigured dynamically to modify their performance. Usually a reconfigurable device has a single function associated with it but that function can be altered or controlled. For instance, a tunable antenna can be operated at different frequency bands, however it always works as an antenna that radiates out electromagnetic waves. For this work, the members of UOIT and Carleton University propose a Field Programmable Microwave Substrate (FPMS) that can perform multiple functions using a single device. This new concept was recently introduced by the principal applicant in 2016. The design was realized using a single microwave waveguide that was programmed to work as an oscillator as well as a filter. The idea thus introduced can provide ground-breaking innovation for dynamically definable/reconfigurable wireless components. The nomenclature of the concept was adopted from field programmable gate arrays (FPGA) due to the commonality of the implementation. The substrate consists of small unit cells that can be individually reconfigured to have a range of positive dielectric constants or a negative dielectric constant.
The substrate was contained in a metal parallel plate structure. Programming a positive material sandwiched between two negative material sidewalls results in a waveguide that behaves in a way described by the slab waveguide equations. Miniaturization and increased density of unit cells can result in lower loss and better performance. Implementations of the FPMS have been presented in low gigahertz frequency range. The FPMS concept promises a new era of programmable microwave circuit and antenna design for various applications like cognitive radios, internet of things (IoT), self-adapting systems etc.

First the research aim of this project is to design unit cells with an analytical model to finally optimize each cell in order to model completly the FPMS for particular reconfigurable devices. Simple microwave functions (waveguides, .) will be used to validate the analytical modelization.

The second objective of the projetc is to use this artificial maetrail up to millimeter waves that will require technological developments due to the size reduction of unit cell but also for the integration of actives devices used in the unit cell to achieve reconfigurability.

The third objective is to design and to realize complex reconfigurable circuits (filters, phase shifters, switches, power dividers) and reconfigurable antennas to obtain evolutive radiation patterns (beam scanning, beamforming) that are main parts of the new wireless systems and radars.

The consortium of this international project is composed of Xlim and IETR for France and UOIT, Carleton University and one industrial partner ORBCOMM for Canada.