Design and implementation of a microwave cavity resonator for modulated backscattered wave

Download
2015
Akkoç, Ahmet
In this study, the device called “Theremin’s Bug” which is a passive microwave cavity resonator is analyzed in detail and a similar device is designed, simulated and implemented. The device being the predecessor of modulated backscatter wave communication devices, RFID devices and microwave wireless sensors is invented by Russian inventor Leon Theremin in 1940s, and used as a covert spy device. The structure is totally passive and contains no electronic component and no battery. It uses the modulation of backscattering electromagnetic waves technique and resembles a passive microphone since it reflects the incoming wave by modulating with the ambient sound. Since the device was a secret, there is no exact information about the technical details and principle of operation of the device. All the information about the device is consisted of stories and tales. And there are many technical inconsistencies about the device and working principle. In this work, the device is studied analytically and a practical prototype is implemented.

Suggestions

Analysis and design of passive microwave and optical devices using the multimode interference technique
Sunay, Ahmet Sertaç; Birand, Mehmet Tuncay; Department of Electrical and Electronics Engineering (2005)
The Multimode Interference (MMI) mechanism is a powerful toool used in the analysis and design of a certain class of optical, microwave and millimeter wave devices. The principles of the MMI method and the self-imaging principle is described. Using this method, NXM MMI couplers, MMI splitter/combiners are analyzed. Computer simulations for illustrating the "Multimode Interference Mechanism" are carried out. The MMI approach is used to analyze overmoded 'rectangular metallic' and 'dielectric slab' type of wa...
An interface circuit prototype for a vibration-based electromagnetic energy harvester
Rahimi, Arian; Zorlu, Ozge; Külah, Haluk; Muhtaroglu, Ali (2010-12-01)
This paper describes the interface electronics for a vibration based Electromagnetic (EM) energy harvester, which works on the mechanical frequency-up-conversion principle. The interface electronics is used to step up and rectify the harvested AC signal of the energy harvester through a two-stage charge-pump circuit. Output voltage of 4.5 V with 2.5% ripple has been demonstrated at a load current of 5 μA. The maximum power efficiency is 35% with an output voltage and current range of 2-2.5 V and 15-20 μA re...
Design and realization of a broad band antenna loaded with a metamaterial-inspired lens for subsurface microwave imaging applications
Yeşilyurt, Ömer; Sayan, Gönül; Department of Electrical and Electronics Engineering (2019)
Ultra-wideband antennas are critical sensors for microwave imaging. In this work, radiation performance of an antipodal Vivaldi antenna is enhanced by using a broadband metasurface lens structure in 1-6 GHz bandwidth. Radiation pattern for the lens integrated antenna is more directive due to electromagnetic properties of the metasurface lens. In order to create such a lens, electrically responsive metamaterial unit cells with high effective permittivity values are designed. As we want to obtain a broadband ...
Design and characterization of a buckling-resistant perforated MEMS membrane under residual stress
Bozyigit, Mustafa Anil; Sahin, Asaf Behzat; Bayram, Barış (2020-05-01)
Micro Electro Mechanical Systems (MEMS) membranes are utilized as both transmitter and receiver in acoustic and ultrasound applications. Their operating frequency ranges are determined by their resonance frequencies. Thus, the resonance frequency estimation is one of the most critical parts of the membrane design. In this study, two perforated circular MEMS membranes are designed, microfabricated and characterized to get proper operation under residual stress since this stress might cause buckling of the me...
Design and prototyping of second generation METU MEMS electromagnetic micro-power generators
Turkyilmaz, Serol; Külah, Haluk; Muhtaroglu, Ali (2010-12-01)
This paper presents an electromagnetic (EM) vibration to electrical power generator which can effectively harvest energy from low frequency external vibrations. The reported second generation MEMS energy scavenger module up-converts low frequency environmental vibrations before mechanical-to-electrical conversion. Power is generated through planar electromagnetic induction using a magnet on the low frequency actuation plane, and coils on the high frequency resonance plane. The proposed approach has been dem...
Citation Formats
A. Akkoç, “Design and implementation of a microwave cavity resonator for modulated backscattered wave,” M.S. - Master of Science, Middle East Technical University, 2015.