Dielectric filter, duplexer, and communications device

A duplexer, comprising a transmitter filter and a receiver filter, wherein

• at least one of the transmitter filter or the receiver filter is a dielectric filter comprising:
• a dielectric body, wherein a surface of the dielectric body is covered with a conductive layer;
• a wideband filtering structure comprising a groove and at least one first resonator, wherein:
• the groove is disposed on a first surface of the dielectric body and is configured to adjust a frequency position of the passband of the wideband filtering structure;
• the first resonator comprises a through hole and an open loop, the through hole penetrates the bottom of the groove and a second surface of the dielectric body, and a hole wall of the through hole is covered with the conductive layer;
• the open loop is located on a bottom surface of the groove and is disposed around an opening of the through hole;
• and
• a side surface of the groove and a part, other than the open loop, of the bottom surface of the groove are covered with the conductive layer;
• a narrowband filtering structure comprising at least one second resonator, which comprises a blind hole disposed on the first surface or the second surface of the dielectric body, wherein a hole wall and a bottom surface of the blind hole are covered with the conductive layer;
• and the first surface and the second surface of the dielectric body are disposed oppositely;
• wherein both the wideband filtering structure and the narrowband filtering structure are disposed in the dielectric body;
• a passband of the narrowband filtering structure is located within a passband of the wideband filter structure.

A communications device, comprising a duplexer which comprises a transmitter filter and a receiver filter, wherein at least one of the transmitter filter or the receiver filter is a dielectric filter comprising:

• a dielectric body, wherein a surface of the dielectric body is covered with a conductive layer;
• a wideband filtering structure comprising a groove and at least one first resonator, wherein:
• the groove is disposed on a first surface of the dielectric body and is configured to adjust a frequency position of the passband of the wideband filtering structure;
• the first resonator comprises a through hole and an open loop, the through hole penetrates the bottom of the groove and a second surface of the dielectric body, and a hole wall of the through hole is covered with the conductive layer;
• the open loop is located on a bottom surface of the groove and is disposed around an opening of the through hole;
• and
• a side surface of the groove and a part, other than the open loop, of the bottom surface of the groove are covered with the conductive layer;
• a narrowband filtering structure comprising at least one second resonator, which comprises a blind hole disposed on the first surface or the second surface of the dielectric body, wherein a hole wall and a bottom surface of the blind hole are covered with the conductive layer;
• and the first surface and the second surface of the dielectric body are disposed oppositely;
• wherein both the wideband filtering structure and the narrowband filtering structure are disposed in the dielectric body;
• a passband of the narrowband filtering structure is located within a passband of the wideband filter structure.