Cascaded surface wave device filters providing balanced and unbalanced signal connections

A cascaded surface wave device filter comprising:

• a first 2-pole surface wave device filter, the first filter having an input port and an output port, one of the ports providing an unbalanced signal connection and the other of the ports providing a balanced signal connection to the first filter:
• a second 2-pole surface wave device filter, the second filter having an input port and an output port one of the ports providing an unbalanced signal connection and the other of the ports providing a balanced signal connection to the second filter:
• and
• a cascade connection of the first filter with the second filter, the cascade connection connecting together the unbalanced signal connections of the first and second filters, whereby the filter comprises a 4-pole filter having balanced input and output ports.

A cascaded surface wave device filter comprising:

• a first 2-pole longitudinally coupled double mode surface wave resonator filter, the first filter having an input port providing a balanced signal connection and an output port providing an unbalanced signal connection to the first filter;
• and
• a second 2-pole longitudinally coupled double mode surface wave resonator filter, the second filter having an input port providing an unbalanced signal connection and an output port providing a balanced signal connection to the second filter;
• wherein the first filter and the second filter are connected together in cascade by an unbalanced signal connection between the input port of the second filter and the output port of the first filter, whereby the cascaded surface wave device filter comprises a 4-pole filter having balanced input and output ports.