# Objective

I'm interested in evaluating the suitability of a standard-gain pyramidal horn for an ultrawideband (UWB) signal. However, I've had difficulty finding reliable information about the phase response over frequency that would be needed to make this determination.

# Background

## UWB Definition

In this context, use the FCC's definition of UWB, the relevant parts of which are:

• Operates in the 3.1 GHz to 10.6 GHz range
• Bandwidth greater than 500 MHz

The application I have in mind will not need to work over every frequency in that band, just a subset of it that is approx 500-2000 MHz wide.

## Considerations w/ Wideband Antennas

There are many types of "wideband" antennas that can easily meet the bandwidth requirement (log periodic, horn, etc.). However, a good UWB antenna should also have these properties (according to [1]):

• Linear phase over the signal bandwidth
• Constant phase center over signal bandwidth

These conditions are necessary to prevent the UWB pulse from being distorted during transmission/reception. This is relevant to point out because many "wideband" antennas violate these conditions. E.g. a log-periodic antenna has a phase center that changes with frequency (i.e. as the frequency changes the active region changes), and some wideband antennas may have a relatively flat gain response over frequency, but might not have a linear phase over the entire band of interest.

# Question

Does a pyramidal horn antenna meet these requirements?

# References

[1] Stutzman, Warren L., and Gary A. Thiele. Antenna theory and design. John Wiley & Sons, 2012.