In the Name of Allah, The Most Gracious, Most Merciful
Dear noble brothers, Zakat in general is obligatory upon the rich, however, Allah, Exalted and Sublime be He, ordains Zakat ul Fitr in Ramadan, but on whom? On those who possess their daily bread. Thus, whoever possesses one meal should pay Zakat ul Fitr.
Allah, Exalted and Sublime be He, decreed that the poor should taste the sweetness of giving at least once a year, and He decreed that the rich should taste poverty. Zakat ul Fitr is obligatory upon you, given Siyaam will not be accepted without paying Zakat ul Fitr.
As I have just mentioned, it is compulsory on every Muslim who owns one meal. Hence, Allah decreed that Zakat ul Fitr is meant to let people taste the sweetness of giving.