1. Characteristic Impedance (Z₀) is the ratio of voltage to current for a wave propagating along the line. It's calculated as Z₀ = √(L/C), where L is inductance and C is capacitance per unit length.

2. Propagation Constant (γ) describes how the wave propagates along the line. It's complex, with γ = α + jβ, where α is the attenuation constant and β is the phase constant.

3. Wavelength (λ) is the distance over which the wave's phase repeats. It's calculated as λ = 2π/β, where β is the phase constant.

4. Efficiency shows how much of the power is delivered to the load compared to the total power in the system. Higher efficiency means less power loss in the transmission line.