This thesis deals with RFID tags design. It comprises an overview of the RDIF technology while focusing upon the passive tags in UHF band. The CST Microwave studio software has been used for draft simulations. The resulting tags have been subjected to parameter measuring – the reflection coefficient, the minimum capacity needed to switch on the tag, the maximum reading distance. The influence of the proximity of metal objects and other materials has also been examined.

The objective of this paper is to present an efficient miniaturized antenna design and simulation of a highly isolated multi-port micro-strip antenna for multiple-input multiple-output communication (MIMO) systems. Three geometric configurations were proposed and compared to achieve an isolation of as low as –30 dB without affecting the antenna performance greatly. The antenna was designed to operate at a resonance frequency of 2.45 GHz (fc ). Ferrite material beneath each meander structure was used for miniaturization purposes as well as an FR4 substrate with a compact overall area of .75 lambda0 ×.5 lambda0 for a system board, where lambda0 is the free space wavelength. A ground plane with small etched slits was used for isolation purposes. A maximum gain of 4.6 dBi in the azimuthal plane was achieved. Index Terms: MIMO, meander antenna, four-port antenna, defected ground structure / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science

This thesis deals with RFID tags. In the first part of the thesis, the general overviews of the present-day RFID systems are presented. This part of the thesis is focused on the passive back-scatter UHF tags and the advantages of their application in supply chain usage. Subsequently, the electromagnetic simulators CST Microwave Studio and IE3D Zeland are described. These simulators were used to design loaded meander antennas. The antennas were designed for different materials and frequency bands of 867 MHz and 2.4 GHz. The designed antennas were made without as well as with the reflector which allows using the antennas in the vicinity of metals. Produced antennas were experimentally tested in the company METRA Blansko Inc, where one of the most significant characteristics of passive RFID tags – the read range was observed.

Currently, there is no equipment to measure the real-time fit of EHMR or N-95masks which are used in harsh environments. Improper fit of these EHMRs or N-95 masks exposes the personnel to hazardous environments. Surface acoustic wave (SAW) sensors have been around for few decades and are being used in various applications. In this work, real-time PM2.5 detection using passive wireless SAW sensors is presented. The design of meander antenna at 433MHz for wireless interrogation of SAW sensor using HFSS and ADS is also presented in this thesis. This works also includes the design of YZ-lithium niobate SAW sensor including COMSOL simulation.