.90 Resonator 3 +/-90 Resonator 2 Resonator 4 +90 % 2 +/90 90 o -20 Housing cut away -30 -40 Resonator 1 Probe between resonators I and 4 provides capacitive -70 coupling -80 -90 -10o9501960197019801902020102020203020402050 Frequency,MHz