Atomizer for electronic cigarette, and cartridge and electronic cigarette having the same

An atomizer for an electronic cigarette, comprising:

• a housing, wherein an E-liquid storage chamber, an aerosol passage, and an atomizing chamber communicating with the aerosol passage are located in the housing;
• and at least one gas inlet communicating with the atomizing chamber and an inspiratory mouth communicating with the aerosol passage are located on the housing, wherein the gas inlet is located on a side surface of the housing;
• and the housing has a length direction, a width direction, and a thickness direction, wherein a dimension of the housing in the thickness direction is D, a dimension of the housing in the length direction is L, and a dimension of the housing in the width direction is W, in which D, L and W meet:
• L>W≥D, 5≤L/D≤9, and 2≤W/D≤5;
• and
• an atomizing core fixing member located in the housing, wherein the atomizing core fixing member separates the E-liquid storage chamber from the atomizing chamber, and the atomizing core fixing member is provided with an atomizing core;
• wherein the atomizing core communicates with the E-liquid storage chamber and the atomizing chamber respectively, and the atomizing core is configured to atomize a medium to be atomized in the E-liquid storage chamber;
• and at least one atomization guide channel is defined between the atomizing core fixing member and an inner wall of the housing, the at least one atomization guide channel is separated from the E-liquid storage chamber, and the atomization guide channel communicates with the aerosol passage and the atomizing chamber.