Broadband Planar Antennas PDF Download

Applications utilizing the millimeter wave spectrum include short range data transfer, imaging, and sensing systems. The advantages of the millimeter wave bands include increased imaging resolution, increased geographic spectrum reuse, and increased bandwidth. Planar antennas can be fabricated using common photolithographic techniques to a high degree of precision and can be integrated on chip or in the package, which simplifies construction while reducing cost and size. The research presented here focuses on the development of broadband planar millimeter wave radiators for on chip and in package integration. Each environment poses unique challenges. The package environment allows more flexibility in the choice of substrates and can accommodate larger antennas, but substrate loss and metal thickness combined with the parasitics of the chip to antenna interconnect typically limit its use to sub 100 GHz frequencies. The on chip environment simplifies the chip to antenna interconnect but complicates the antenna design due to the low resistivity of the semiconductor substrate, thin dielectric layers, and small available area. A uniplanar broadband modified aperture bowtie antenna for package integration is developed in this work, yielding 41% bandwidth at a center frequency of 73 GHz on a low cost FR408 substrate. The antenna is designed for transmission in both the upper and lower hemispheres for low directivity applications. The use of FR408 laminate reduces package cost compared to other common millimeter wave substrates, such as liquid crystal polymer (LCP) and polytetrafluoroethylene (PTFE). An on chip broadband antenna has also been developed utilizing a photo definable SU-8 dielectric and an enhanced electromagnetic band gap (EBG) reflector. Post-processed resists can function as dielectrics. SU-8 allows layer thicknesses of up to a few hundred micrometers which improves performance but increases surface waves effects. The electromagnetic band gap (EBG) structure suppresses these surface waves improving radiation performance. This work demonstrates SU-8 as a multilayer dielectric to support the uniplanar antenna for performance from 180 to 300 GHz.