The Residual-Wave Current Excited on a Printed-Circuit Line: A Source of Spurious Effects

Abstract

The excitation of a new type of current wave on printed-circuit lines by a practical source, such as a delta-gap source, is examined. This new type of current wave is called a residual-wave current, and corresponds to that portion of the continuous-spectrum current that is separate from the leaky-mode currents. A source on a printed-circuit line will excite bound modes, leaky modes, and one or more residual-wave currents. The residual-wave currents may be responsible for spurious transmissions effects. This is demonstrated by numerical calculations on stripline and microstrip, which account for the delta-gap source.

Properties of CPW in the sub-mm wave range and its potential to radiate

“…The 8th leaky wave is substituted for the 7th wave around 700 GHz. This means that the field propagating over the CPW in the sub-mm wave range consists of consecutive higher order surface leaky waves, complemented probably by residual waves [9], depending on the source.…”

Space leakage of power from uniplanar transmission lines

“…We have shown that the coplanar waveguide is also able to leak power into space in the form of the 1stSL C2 . We presume that all waves identified and quoted above are a part of the total field excited by a real source which in a different approach [5] is called a "residual wave". Nevertheless there are several features typical of a few open transmission lines which can be considered general.…”