with a power field of hf em waves by one or more transmitting antennas made from metallic sheets or wires application_number US 88248801 A description 0081 6 26 31 32 38 39 40 42 44 45 47 49 52 and 53 are various types of transmitting antennas 0085 10 and 11 are forward v f and reflected v r voltages respectively 0086 12 14 13 and 15 are the rc high pass filters hpf 0087 17 and 18 are the extracted variable signals from the basic v f and v r voltages 0089 20 is an o p signal v e from the equation processor block 0112 56 is an rf tank inside the bidirectional coupler 0113 57 is a circuit for achieving a symmetrical bidirectional coupler 0116 60 and 61 are rf form forward v f and reflected v r voltages respectively 0117 62 and 63 are dc blocking ac coupling capacitors 0120 68 73 74 and 77 are rf suppression chokes the device structure according to the invention for all the applications aforementioned has generally the same configuration the slight difference in specification between each individual application is due to the difference in the requirements from one application to another these differences will be explained in the related sections referring to the drawings and more particularly to fig1 the first part of.