Multi-mode microwave power measurement utilizing oversized measuring waveguide section to obtain plane wave propagation

Claim 1

IN THE MEASUREMENT OF MULTI-MODE ELECTRO-MAGNETIC WAVE POWER PROPAGATING IN A WAVEGUIDE BY MEASURING THE FIELD STRENGTHS AT A PLURALITY OF POINTS ALIGNED TRANSVERSELY TO THE DIRECTION OF PROPAGATION AND UTILIZING THE MEASUREMENTS TO PROVIDE AN INDICATION OF THE POWER, APPARATUS WHICH COMPRISES A FIRST WAVEGUIDE SECTION, A SOURCE OF ELECTROMAGNETIC WAVES COUPLED TO SAID FIRST WAVEGUIDE SECTION AND SUPPLYING THERETO ELECTROMAGNECTIC WAVES AT A FUNDAMENTAL FREQUENCY AND ALSO SUPPLYING WAVES AT FREQUENCIES HIGHER THAN SAID FUNDAMENTAL FREQUENCY THAT PROPAGATE IN SAID FIRST WAVEGUIDE SECTION IN A PLURALITY OF MODES HIGHER THAN THEIR DOMINANT MODES, A MEASURING WAVEGUIDE SECTION POSSESING PROPAGATING CHARACTERISTICS FOR SAID WAVES IN SAID HIGHER MODES THAT YIELD CUTOFF FREQUENCIES THEREIN WHICH ARE SUFFI CIENTLY BELOW THE CUTOFF FREQUENCIES OF LIKE MODES IN SAID FIRST WAVEGUIDE SECTION TO OBTAIN SUBSTANTIALLY PLANE WAVE PROPAGATION OF SAID WAVES IN SAID MEASURGING WAVEGUIDE SECTION, COUPLING MEANS FOR COUPLING SAID MEASURING WAVEGUIDE SECTION WITH SAID FIRST WAVEGUIDE SECTION TO SUPPLY SAID WAVES IN SAID PLURALITY OF MODES TO MEASURING WAVEGUIDE SECTION, AND SAMPLING MEANS FOR SAMPLING THE FIELD STRENGTHS OF THE WAVES IN SAID HIGHER MODES AT A PLURALITY OF POINTS ALIGNED TRANSVERSELY TO THE DIRECTION OF WAVE PROPAGATION IN SAID MEASURING WAVEGUIDE SECTION, THE SAMPLED FIELD STRENGTHS BEING USEFUL FOR PROVIDING INDICATIONS OF THE POWER OF ELECTROMAGNETIC WAVES PROPAGATING IN SAID HIGHER MODES.