Patent ID: 7135943

Claim:
A lumped-element diplexer implemented in a multi-layered substrate comprising: a low-pass filter circuit comprising: a first capacitor plate disposed on a first layer of the multi-layered substrate; a second capacitor plate disposed on a second layer of the multi-layered substrate; and a first inductor plate directly disposed on a third layer of the multi-layered substrate; a high-pass filter circuit, the high-pass filter circuit comprising: a third capacitor plate disposed on a fourth layer of the multi-layered substrate; a fourth capacitor plate disposed on a fifth layer of the multi-layered substrate; a fifth capacitor plate disposed on a sixth layer of the multi-layered substrate; and a second inductor plate directly disposed on a seventh layer of the multi-layered substrate; and a ground plane forming a base of the multi-layered substrate, wherein circuit elements of the low-pass filter circuit are disposed on a first series of layers of the multi-layered substrate, a first end of the low-pass filter circuit is connected to a first port and a second end of the low-pass filter circuit is connected to a second port, circuit elements of the high-pass filter circuit are disposed on a second series of layers of the multi-layered substrate, a first end of the high-pass filter circuit, is connected to the first port and a second end of the high-pass filter circuit is connected to a third port, elements of the filter circuits are orientated horizontally with respect to the ground plane and are arranged in layers aligned substantially vertically, these layers being separated by a dielectric material and inter-layer connections being implemented by at least a via, and no layer is between an uppermost layer of the first series of layers of the multi-layered substrate and a lowermost layer of the second series of layers of the multi-layered substrate.