Split-type, half-lattice micro-acoustic filter using a phase shifter and having broad bandwidth

A micro-acoustic RF filter, comprising:

• a first port and a second port;
• a first node coupled to the first port;
• a second node coupled to the second port;
• a first signal path coupled between the first node and the second node, the first signal path including a first resonator;
• a second signal path coupled between the first node and the second node, the second signal path including a second resonator and a phase shifter connected in series to the second resonator, wherein at least one of the first resonator or the second resonator comprises a micro-acoustic resonator;
• a third resonator, wherein the third resonator comprises an additional micro-acoustic resonator having a first end coupled directly to the second node and a second end coupled to a reference node;
• and
• a fourth resonator having a first end coupled to the first port and a second end coupled directly to the first node,
• wherein the third resonator and the fourth resonator are configured to provide a finite transmission zero (FTZ) function outside of a passband, and
• wherein the first resonator, the second resonator, and the phase shifter configure a frequency response within the passband, and
• wherein each of the first resonator, the second resonator, and the fourth resonator comprise a pair of resonators connected in anti-series having opposite polarities.