High frequency filter and multiplexer

A high frequency filter comprising:

• a piezoelectric substrate;
• a first signal electrode and a second signal electrode on the piezoelectric substrate;
• a filter circuit portion on a first path between the first signal electrode and the second signal electrode;
• and
• an additional circuit portion on a second path parallel or substantially parallel to at least a portion of the first path;
• wherein
• the filter circuit portion includes one or more series arm resonators on the first path, one or more parallel arm resonators on a path connecting the first path and a ground, and an inductor on a path connecting the ground and a portion or all of parallel arm resonators among the one or more parallel arm resonators;
• the additional circuit portion includes an acoustically coupled resonator including a plurality of acoustic wave resonators;
• each of the plurality of acoustic wave resonators includes a first electrode and a second electrode opposing the first electrode;
• the first electrode is connected to the second path;
• and
• the second electrode is connected to a connection conductor on a path connecting the portion or all of parallel arm resonators and the inductor.