Configuration provided below. The Phone is connected to ge-7/0/9.
 
U15499@JUEX62CMPSW-51.TRV> show configuration access
radius-server {
    10.100.91.193 {
        port 1812;
        secret "$9$Vews4JGiPT3dbs4aJDjCtpBhS"; ## SECRET-DATA
        source-address 10.100.13.25;
    }
}
profile juniper-radius-profile {
    authentication-order radius;
    radius {
        authentication-server 10.100.91.193;
    }
    accounting {
        order radius;
        accounting-stop-on-failure;
        accounting-stop-on-access-deny;
    }
}
{master}
U15499@JUEX62CMPSW-51.TRV> show configuration protocols dot1x
inactive: traceoptions {
    file dot1x size 1m files 2;
    flag all;
    flag dot1x-debug;
}
authenticator {
    authentication-profile-name juniper-radius-profile;
    interface {
        inactive: ge-3/0/15.0 {
            supplicant multiple;
            transmit-period 5;
            reauthentication 600;
            supplicant-timeout 5;
            server-timeout 5;
        }
        ge-7/0/9.0 {
            supplicant single;
            transmit-period 5;
            mac-radius {
                restrict;
            }
            reauthentication 600;
            supplicant-timeout 5;
            server-timeout 5;
        }
    }
}
{master}
U15499@JUEX62CMPSW-51.TRV>