Planar waveguides are an important type of waveguide that can be used in integrated circuits to connect microwave circuit elements. Examples include strip lines, microstrip lines, coplanar waveguides, and slotted lines. When designing a planar waveguide circuit, its characteristic impedance, dispersion, phase velocity, attenuation, and other parameters must be determined. Commercial software tools can help with designing waveguides to meet specifications for impedance and phase shift. Planar waveguides find applications in microwave integrated circuits, filters, phase shifters, and feeding energy from generators to antennas.