  Antireflection or impedance matching is a topic that has been extensively
researched by the optical and microwave communities over the past century and
until today. However, due to the diverging wave impedances of TE (s) and TM (p)
polarizations with increasing incident angle, it is impossible to achieve
perfect matching simultaneously for both polarizations at an oblique incident
angle with a single conventional matching layer. In this paper, we show that
simultaneous perfecting matching of an arbitrary substrate at an arbitrary
incident angle from air is possible with a single uniaxial metamaterial
matching layer (UMML) that possesses specific permittivity and permeability
tensors. We demonstrate this concept by synthesizing a physical UMML to match a
high-index ({\epsilon}r= 10.2) substrate at 45{\deg}. The required permittivity
and permittivity tensors of the UMML are achieved through the judicious control
of the tangential and longitudinal electric and magnetic responses. Around -30
dB reflections are observed for both polarizations at the design angle.
Building on the UMML concept, we design a novel radome in microwave regime with
a near omni-directional matching performance. For incident angles from
0{\deg}-85{\deg}, reflections remain below -14 dB for both polarizations. To
our best knowledge, this is the widest angular range that has been achieved
while maintaining less than 5% power reflection for both polarizations. The
proposed UMML concept offers a new paradigm for designing high-performance
microwave, terahertz, and optical devices.
