Abstract: The specification relates to a radio frequency (RF) multiport, multiband semiconductor and transmission circuit. Each port in the multiport circuit is linked to a second port utilizing a semiconductor switching leg. A semiconductor switching leg is biased to either transport thereover an RF signal or to prevent its transport. In an embodiment of the present invention utilizing diodes as an active device within each semiconductor switching leg, a DC biasing signal is applied through an inlet and outlet inductor, thus allowing DC current to pass through the diode for biasing, but preventing RF signal loss to ground. Capacitors are used for RF signal coupling and DC blocking. One embodiment of the present invention is utilized with a dual band cellular/PCS device, with either band selectable for transmission and reception over either an internal antenna or, in the alternative, an external antenna port.