RFID Tags for On- and Off-Metal Applications

In one embodiment, a radio-frequency identification (RFID) tag including a substrate having a top surface, bottom surface, opposed end surfaces, and opposed lateral surfaces, a passive RFID integrated circuit (IC) chip mounted to the top surface of the substrate, a monopole antenna that includes a planar radiating arm that extends out from the RFID IC chip along the top surface of the substrate and a matching loop having two grounded matching stubs that surround the chip and a portion of the radiating arm, and a ground plane formed on the bottom surface, an end surface, and the top surface of the substrate, the ground plane being electrically coupled to the matching stubs and the radiating arm

Apertured Waveguides for Electromagnetic Wave Transmission

In some embodiments, an apertured waveguide includes a wall comprising a plurality of apertures and an interior channel along which electromagnetic waves can propagate, the interior channel being defined at least in part by the wall

A novel noncontacting waveguide backshort for submillimeter wave frequencies

A novel noncontacting waveguide backshort has been developed for millimeter wave and submillimeter wave frequencies. It employs a metallic bar with rectangular or circular holes. The size and spacing of the holes are adjusted to provide a periodic variation of the guide impedance on the correct length scale to give a large reflection of rf power. This design is mechanically rugged and can be readily fabricated for high submillimeter wave frequencies where conventional backshorts are difficult or impossible to fabricate. Model experiments have been performed at 4 GHz – 6 GHz to empirically optimize the design parameters. Values of reflected power greater than 95% over a 30% bandwidth have been achieved. A specific design is presented which has also been successfully scaled to WR-10 band (75 GHz – 110 GHz). A theoretical analysis is compared to the experiments and found to agree well with the measured data.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44554/1/10762_2005_Article_BF02085860.pd

Micromachined membrane filters for microwave and millimeter-wave applications (invited article)

Recent developments in micromachining techniques at the University of Michigan have resulted in novel high-performance low-loss filters for microwave and millimeter-wave applications. The idea is based on suspending the filters on thin dielectric membranes to eliminate dielectric loss and dispersion problems, resulting in a pure TEM mode of propagation and conductor-loss-limited performance. The dielectric membrane and the surrounding cavities are built using chemical etching in Silicon and GaAs wafers. The filters are therefore compatible with low-cost IC fabrication techniques and can be combined with planar diodes and transistors to result in active filter networks. Several state-of-the-art filters have been realized including 15-GHz and 20-GHz bandpass interdigital suspended stripline filters, lowpass and bandpass microshield filters at 30 GHz and 90 GHz, microstrip 94-GHz bandpass filters, and a 250-GHz bandpass filter with 1.0–1.5-dB insertion loss. This article reviews the associated fabrication techniques, the different types of transmission lines achieved using this technology, and the measured performance from 15 to 350 GHz. The study concludes with a detailed description of the future work in this area. © 1997 John Wiley & Sons, Inc. Int J Microwave Millimeter-Wave CAE 7: 149–166, 1997.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/35146/1/1_ftp.pd

Micromachined high frequency transmission lines on thin dielectric membranes

http://deepblue.lib.umich.edu/bitstream/2027.42/8238/5/bad3619.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/8238/4/bad3619.0001.001.tx

On-body, inward-facing antennas

In some embodiments, an antenna includes a dielectric substrate having a first surface and a second surface opposite to the first surface, a planar central antenna element provided on the first surface, and a planar electromagnetic bandgap structure provided on the first surface and surrounding the central antenna element

Compact dual-channel transceivers

In one embodiment, a method for monitoring a structure includes associating a passive sensor with the structure, the sensor being configured to measure a physical parameter of the structure that is indicative of the structure\u27s condition, associating a dual-channel transceiver with the structure, the transceiver having a sensing repeater that operates on a first channel and a reference repeater that operates on a second channel, wherein the sensing repeater is connected to the passive sensor, receiving with a receive antenna of the reference repeater an interrogation signal transmitted from an interrogation device, multiplying a frequency of the received interrogation signal with the reference repeater to generate a reference response signal having a multiplied frequency, and transmitting the reference response signal with the reference repeater to the interrogation device

On-body, inward-facing antennas

In some embodiments, an antenna includes a dielectric substrate having a first surface and a second surface opposite to the first surface, a planar central antenna element provided on the first surface, and a planar electromagnetic bandgap structure provided on the first surface and surrounding the central antenna element

Compact stubs and filters for micromachined coplanar waveguide

http://deepblue.lib.umich.edu/bitstream/2027.42/8236/5/bad3673.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/8236/4/bad3673.0001.001.tx

Compact stubs for micromachined coplanar waveguide

http://deepblue.lib.umich.edu/bitstream/2027.42/8236/5/bad3673.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/8236/4/bad3673.0001.001.tx