  The bowtie antenna is a topic of growing interest in recent years. In this
paper, we design, fabricate, and characterize a modified gold bowtie antenna
integrated on a transparent silica substrate. The bowtie antenna is designed
with broad RF bandwidth to cover the X-band in the electromagnetic spectrum. We
numerically investigate the antenna characteristics, specifically its resonant
frequency and enhancement factor. Our designed bowtie antenna provides a strong
broadband electric field enhancement in its feed gap. Taking advantage of the
low-k silica substrate, high enhancement factor can be achieved without the
unwanted reflection and scattering from the backside silicon handle which is
the issue of using an SOI substrate. We simulate the dependence of resonance
frequency on bowtie geometry, and verify the simulation results through
experimental investigation, by fabricating different sets of bowtie antennas on
silica substrates and then measuring their resonance frequencies. In addition,
the far-field radiation pattern of the bowtie antenna is measured, and it shows
dipole-like characteristics with large beam width. Such a broadband antenna
will be useful for a myriad of applications, ranging from photonic
electromagnetic wave sensing to wireless communications.
