Both 受動態 and 受身形 mean passive voice and they are exactly same. Also there are no "corresponding" antonym for 受身形.
This is extra advice: the sentence 私の車が田中さんに盗まれた。is grammatically correct and there is no room for misunderstanding, but sounds unnatural a little bit. The improved sentence would be like 私の車は田中さんによって盗まれた。
The postpositional particle "に" indicates doer in sentences with passive voice, but also indicates direction in general. So you can show the function of "に" more clearly by adding "よって". Furthermore, "が" specifies objects stronger than "は". For example, while 私は田中だ。means "I am Tanaka," 私が田中だ。means "I am none other than Tanaka." So unless you want to emphasize the fact that it is nothing other than your car that is stolen, using "は" is recommended. However, if a sentence have a clause:
(It is pity that my car was stolen by Mr. Tanaka.)
and if "は" is used in main part, then it is better to use "が" instead of "は" because the content of the clause is worth emphasizing; otherwise we won't use clause.