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This paper presents the complete process of design theory, manufacturing, and testing of microstrip rectennas at the University of North Dakota. The rectenna is an antenna integrated with a rectifying circuit. Patch antennas resonating at 2.45 GHz were simulated, manufactured and tested. Simulated and measured results were compared. Furthermore, a microwave rectifier was designed, manufactured, and tested for its impedance matching and rectification efficiency from AC to DC. Efficiency of 21% was achieved at a power input of 15dBm for 2.45 GHz. The combination of antenna and rectifier was tested for overall efficiency [ABSTRACT FROM AUTHOR]

In this paper, we introduce a novel microwave tomography system, which utilizes 24 double-layered Vivaldi antennas, each of which is equipped with a diode-loaded printed-wire probe. By biasing the probe's diodes, the impedance of the probe is modified, allowing an indirect measurement of the electric field at the probe's locations. Each printed-wire probe is loaded with five equally spaced p-i-n diodes, in series. We show that electric field data collected in this way within the proposed tomography system can be used to reconstruct the dielectric properties of an object of interest. Reconstructions for various objects are shown. Although the results are still preliminary, sufficient experimentation has been done to delineate the advantages of such an indirect method of collecting scattered-field data for tomographic imaging purposes. [ABSTRACT FROM PUBLISHER]

A combination method is utilized to design eagle feed Vivaldi antenna.The antenna structure is discretized into arbitrary number of sections whose characteristic impedances and their corresponding dimensions are evaluated using transmission line theory and finite element method, respectively. The proposed antenna is compared with two classical designs, theoretically and experimentally. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:126-133, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26516 [ABSTRACT FROM AUTHOR]

In this paper, the design of a miniature wideband antenna for biotelemetry applications is presented. We propose a biocompatible antenna to be printed on the outer surface of a capsule. The size of the antenna in planar form is 2.52 mm³. The antenna shows a wide impedance bandwidth of 7.31 GHz (0.78 GHz – 8 GHz, for -10dB reflection coefficient) when implanted inside a simple three layer body model. The antenna gain values at 915 MHz and 2.45 GHz are -25.23 dBi and -27.51 dBi, respectively. The antenna resonance frequency is shown to be robust when implanted in a realistic anatomical body model. The performance of the communication link between the implanted antenna and an external half-wavelength dipole at 915 MHz and 2.45 GHz is also presented. [ABSTRACT FROM AUTHOR]