A radio frequency (RF) input signal is typically applied to an input of a home entertainment device, for example, a set-top box via an external coaxial cable, for example, a Multimedia over Coax Alliance (MoCA) cable, having a terminating coaxial connector known as F connector. The set-top box contains electronic components which may be vulnerable to damage from electrical surges. Surges in transmission line voltages, as well as noise, can change the operating range of the components and severely damage and/or destroy them. There are many sources which can cause harmful electrical energy surges. One source is RF interference that can be coupled to transmission lines from a multitude of sources. The transmission lines act as large antennas that may extend over several miles, thereby collecting a significant amount of RF noise power from such sources as radio broadcast antennas. Another source could be lightening. Therefore, it may be desirable to interpose an RF surge suppression device, forming direct current (DC) short or low impedance when a surge occurs. The RF surge suppression device may be coupled to an output of the F connector.
It may be desirable to have the F connector mounted at some distance above a printed circuit board (PCB) of the set-top box, for example, to facilitate easier manufacturing and/or more convenient placement or usage of a lower cost implementation of the connector. In such arrangement, the lead that goes from a center conductor of the connector to a pad in the PCB, the rest of the F connector and the RF surge suppression device may exhibit a reactance that may not be negligible for impedance matching purposes. Additionally, at the PCB, the pad may be relatively large to facilitate machine or reflow soldering. This pad may introduce a stray capacitance to ground that also may not be negligible.
A receiver, such as the set-top box, may receive through the connector an input signal transmitted in a multiple transmission mode system covering a wide range of frequencies, for example, up to 2.15 GHz. It may be desirable to avoid significant input return loss as a result of the aforementioned reactance of the network that includes the connector and the RF surge suppression device. Return loss is a measurement of how well the impedance of a load, including, for example, a filter that is driven by the network, including the connector and the RF surge suppression device, is matched to the characteristic impedance of the network. The return loss is a number associated with a corresponding interface that is calculated from the reflection caused at the corresponding interface as a result of an impedance mismatch. The return loss is usually expressed as a ratio in decibels (dB).