His name would be written as "神田". Those two symbols are refereed to as kanji. The reading of a kanji depends on what word it is used in.

Kamita is literally the combined readings of the words "神"(god-kami) and "田"(field-ta), not their readings for when used in a name, or when combined with other kanji. Additionally, the "t" sound at the beginning of a kanji often becomes a "d" when it is placed in the middle of a word (although it is hit or miss for when this happens).

Out of curiosity, I looked up "神田", and it turns out that it is an (archaic) word, pronounced kamita, meaning "field affiliated with a shrine (the tax-exempt proceeds of its harvest going to pay for shrine operations)" [1]

[1]http://jisho.org/words?jap=%E7%A5%9E%E7%94%B0&eng=&dict=edic...

'Kamita' and 'Kanda' share the same kanji "神田" in japanese and the latter is much popular.

Japanese characters can have multiple readings. For most words and phrases, there is a standard correct reading, but for names, things get more complicated. Presumably 'Kanda' is the most common reading.

http://jisho.org/words?jap=%E7%A5%9E%E7%94%B0&eng=&dict=enam...