Dietmar Pilz

Millimeter-wave folded reflector antennas with high gain, low loss, and low profile

Periodic and quasi-periodic structures, printed on a dielectric substrate, can be employed to control the reflection and transmission properties of incident waves as a function of structure geometry. Local variations of the element geometry on a substrate with backside metallization - resulting in respective variations of the reflection phase angle - can be used to design printed reflectarray antennas. The dual-polarization properties of such antennas, together with polarizing grids or slot arrays, can be exploited for the realization of compact, low-profile folded reflector antennas. Examples of some antennas of this type are presented, covering the 60 GHz range for communication and ISM applications, and 76 to 77 GHz for automotive radars.

Full wave analysis of a planar reflector antenna

The theoretical analysis of a planar reflector antenna consisting of dipoles printed on a conductor backed dielectric sheet illuminated by a waveguide feed horn is presented. The characteristics of the antenna are analysed using the spectral domain method for open structures. Theoretical and experimental results are compared.

A Novel Linear-Circular Polarization Converter

A novel, low-cost linear-circular transmission polarizer is presented, consisting of a single substrat metallized with periodic dipole structures. The dipole arrays on both sides of the substrate are twisted against each other. The non symmetric arrangement leads to novel characteristics concerning the reflection and transmission. The analysis and the design are done by a modified spectral domain method. A Ka-band prototype is built and measured to verify the theoretical results.

Periodic and Quasi-Periodic Structures for Antenna Applications

Printed periodic and quasi-periodic structures can be employed to control reflection and transmission properties of incident waves as a function of structure geometry. As this can be done mostly independently for both polarizations, different kinds of polarizers (reflection and transmission polarizer from linear to circular polarization or twist polarizers) can be realized. A local variation of element geometry allow the design of printed reflector antennas. Including the dual polarization properties for such antennas, dual function or dual frequency antennas can be built, or these properties can be exploited for the realization of compact, low-profile folded reflector antennas. Examples for these structures are presented, includimg antennas for 60 and 77 GHz with a diameter of 100 mm and a depth of 25 mm only.

A folded lens antenna with triple use of the lens

A novel type of folded lens antenna is presented in this contribution. In addition to known concepts of folding reflector or lens antennas, the lens of the antenna described here is used threefold, resulting in a further reduction of antenna depth. Furthermore, a novel type of twist reflector printed on a planar dielectric substrate of given thickness is included. As an example, a test antenna in the 20 GHz range was designed, fabricated and tested, showing good results and giving the basis for compact antennas, especially in the mm-wave frequency range.