15.4.15
You are invited to attend a lecture
By
Iris Shtrasler
(MSc. student under the supervision of Dr. Eran Socher)
School of Electrical Engineering, Tel-Aviv University, Tel-Aviv 69978, Israel
RF CMOS Active Metamaterial-Based Wideband 2-D Controllable Array
In the recent years an increasing interest in metamaterials is observed. By constructing artificial materials with a desired electromagnetic response, metamaterials concepts have been used to develop novel microwave devices. Typically, the major concern of using passive metamaterial devices is the dielectric and ohmic losses that eventually limit their overall performance. Moreover there is a problem to control their properties online.
A possible solution to these concerns is active metamaterials, which enable on-chip active metamaterial integration, with loss compensation and controllability functions.
This thesis presents a new approach of chip-integrated active two-dimensional metamaterials based on lumped elements of capacitors and inductors, which utilize on-chip transistors as switches and gain elements to enable wave propagation control and loss compensation.
The first chip is an innovative topology of an active metamaterial array that has been realized in TSMC 65 nm CMOS process. This new approach utilizes semiconductor processing to implement a 2-D metamaterial array, which has one input and three output ports. To demonstrate the control capability, the microwave signal entering the input port can be routed and/or split between the three output ports, so the controllability is achieved by CMOS switches. The mode of operation of the chip is set by DC control signals. The chip is well matched up to 15GHz, and has low loss at low frequencies in excellent agreement with the simulations.
The second chip has similar topology of a 2-D metamaterial array, but has one input and two output ports and a new approach for loss compensation in metamaterials is presented. Some of the unit cells of the metamaterial are embedded with a cross-coupled transistor pair based negative differential resistance circuit to cancel these losses. Design and simulation results for this chip with and without loss compensation are presented. Simulations indicate that loss can be compensated at about 8dB at a narrow frequency range which is limited only by the maximum operating frequency of transistors, which is reaching terahertz in today’s semiconductor technologies.
Wednesday, April 15, 2015, at 11:15
Room 206, Wolfson Engineering building 2nd floor
