{HEAD ~ The novel circulator} includes {TAIL ~ a substrate}, a predetermined number of microstrip lines disposed on a first surface of the substrate, a ground layer and a predetermined number of electrical contacts disposed on the second surface of the substrate, and a mechanism for coupling each microstrip line to one of the electrical contacts 
includes
{ HEAD ~ The novel circulator } includes { TAIL ~ a substrate } , a predetermined number of microstrip lines disposed on a first surface of the substrate , a ground layer and a predetermined number of electrical contacts disposed on the second surface of the substrate , and a mechanism for coupling each microstrip line to one of the electrical contacts
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH