area where cap 207 is bonded to microstrips 202 and 205 microstrip 202 and 205 becomes stripline and an impedance transformer 215 needs to be provided in the cap area to match the impedance outside the cap wall 216 with the impedance under cap wall 216 impedance transformer 215 takes the form of an alteration in the dimension of the conducting strip beneath the cap wall 216 fig5 c and 5d show a narrowing of the conducting strip 202 and 205 respectively as they pass under the cap wall 216 this narrowing acting as an impedance transformer matches the impedance of the microstrip under cap wall 216 with portions of the microstrip not under cap wall 216 the dimensions of impedance transformer 215 depends on the material of cap 207 in one embodiment impedance transformer 215 is a narrowing to about 23 mils 0 023 inches of the normally 30 mils 0 030 inches microstrip for a length of about 20 mils 0 020 inches under cap wall 216 without impedance transformer 215 in the vicinity of cap wall 216 the tuning of the microwave circuit may deteriorate sufficiently to detrimentally affect the stability of the microwave circuit microwave circuit board assembly 200 shown in fig4 a 4b 4c 5a 5b 5c and 5d is mounted on a base and covered with a lid to form the tripler amplifier module the base and lid form a housing for the tripler amplifier module electrical connections to the microwave circuit are made through the base and lid fig6 a shows a base 300 of the tripler amplifier module on which the.