Coaxial cable is the type of transmission line that accepts the TEM (Transverse Electromagnetic) wave.

Explanation:
A TEM wave is a type of electromagnetic wave that has both electric and magnetic fields perpendicular to the direction of propagation. It is characterized by the absence of any longitudinal component of the electric or magnetic fields.

Coaxial cable is a type of transmission line that consists of two concentric conductors separated by an insulating material. The inner conductor is usually a solid wire, while the outer conductor is a cylindrical metal shield. The insulating material between the conductors is typically a dielectric material.

Reasons why coaxial cable accepts the TEM wave:

1. Inner conductor: The inner conductor of the coaxial cable carries the electric field component of the TEM wave. It is responsible for propagating the electric field from the source to the load.

2. Outer conductor: The outer conductor of the coaxial cable acts as a shield to contain and protect the electric field within the cable. It also carries the return current, which completes the circuit for the electric field.

3. Dielectric material: The insulating material between the inner and outer conductors of the coaxial cable is a dielectric material. This dielectric material helps in maintaining the desired impedance and provides insulation between the conductors.

4. Cylindrical symmetry: The coaxial cable has a cylindrical symmetry, which allows for the propagation of the transverse electromagnetic wave. The fields within the coaxial cable are confined within the cylindrical region, resulting in the TEM mode of propagation.

Advantages of using coaxial cable for TEM wave propagation:

1. Low loss: Coaxial cable offers low loss characteristics, making it suitable for long-distance transmission of signals without significant signal degradation.

2. High bandwidth: Coaxial cable has a wide bandwidth, allowing for the transmission of a broad range of frequencies.

3. Low interference: The outer conductor of the coaxial cable acts as a shield, providing protection against external electromagnetic interference.

4. Flexible and durable: Coaxial cable is flexible and durable, making it easy to install and resistant to environmental factors such as moisture and temperature variations.

In conclusion, coaxial cable is the type of transmission line that accepts the TEM wave due to its structure, which allows for the propagation of transverse electromagnetic fields and provides low loss, high bandwidth, and low interference characteristics.