Feeding Apparatus and Low Noise Block Down-converter

A low noise block down-converter, adapted to a communication receiving device, the low noise block down-converter comprising:

• a feedhorn;
• a waveguide;
• a polarizer;
• and
• a feeding apparatus, comprising:
• a substrate;
• an annular grounded metal sheet, disposed on the substrate, substantially in a shape of an annularity, and having a first opening and a second opening;
• a rectangular grounded metal sheet, disposed on the substrate, extending from the annular grounded metal sheet across an interior of the annularity and corresponding to a configuration of a polarizer of the waveguide;
• a first parasitic grounded metal sheet, extending from a side of the rectangular grounded metal sheet along a first direction;
• a second parasitic grounded metal sheet, extending from another side of the rectangular grounded metal sheet along a second direction, wherein the second direction is substantially opposite to the first direction;
• a first feeding metal sheet, extending from the first opening toward the interior of the annularity and comprising a first portion, a second portion and a third portion, wherein a width of the first portion is different from a width of the second portion, and the width of the second portion is different from a width of the third portion;
• and
• a second feeding metal sheet, extending from the second opening toward the interior of the annularity and comprising a fourth portion, a fifth portion and a sixth portion, wherein a width of the fourth portion is different from a width of the fifth portion, and the width of the fifth portion is different from a width of the sixth portion.