Electromagnetics and Antennas

Broadband Antennas

CRS developed a variety of antennas for broadband (1:10) and multiband operation. These antennas have been used for DF applications, for body-worn applications, and for various communication and surveillance application. An example of a broadband antenna is shown here. It has a specialized backing, making it almost conformal with metallic surfaces.

UHF microwave antenna
L = 20 cm, W = 7.5 cm
Simulated return loss


Measured antenna pattern

The unique structure shown above has been developed by CRS. It has very desirable characteristics for wideband antenna applications. The geometry of the antenna element and the properties of the back material have been carefully engineered to achieve maximum bandwidth and gain with reduced antenna aperture. The conventional antenna suffers from the ground effect of the mounting structures (aircraft or ship body). The CRS antenna uses multiple matching layers, eliminating the destructive image created by the mounting structures. The antenna can be attached to any platform without degrading the antenna performance.

CRS antenna requires only a ¼ wavelength of the antenna length to cover the low-frequency limit of the antenna bandwidth (normally, a half wavelength is required for dipole type). Single-element achieves 1:40 bandwidth and combination of multiple scaled elements enables one to build any arbitrary bandwidth greater than 1:40. A VSWR plot of a sample antenna is shown above. The antenna maintains VSWR<2.5 over 60MHz to 2GHz range (plot only shows up to 1.2GHz).