What polarization has an E-field radiated at a 45 degree angle to the earth's surface?

The concept of polarization in the context of electromagnetic waves refers to the orientation of the electric field (E-field) relative to the Earth's surface. When the E-field is radiated at a 45-degree angle to the Earth’s surface, it is neither purely vertical nor purely horizontal. Instead, this angle represents a type of polarization that is often characterized as slanted.

Slanted polarization effectively combines elements of both vertical and horizontal polarization, making it particularly useful in certain communications and radar scenarios where multipath propagation can occur. The 45-degree angle signifies that the electric field is oriented diagonally, allowing for effective signal propagation in diverse environments.

In contrast, vertical polarization corresponds to an E-field that is aligned straight up and down relative to the ground, while horizontal polarization has the E-field aligned parallel to the ground. Cross polarization typically refers to a specific orientation that is 90 degrees opposite the primary polarization, which does not apply when describing an E-field set at a 45-degree angle. Thus, slanted is the most accurate descriptor for an E-field radiated at this specific angle.