Thanks searcher99 and prusakolep. I got the ticket dismissed today with the motion to suppress Affidavit of Speed.

I went to the court and observed traffic infraction hearings last week. There was an attorney got all his eight cases dismissed in five minutes. Some of them were just because of no signature or date on some documents. I reviewed my discovery materials again, and found there was no signature or even name on the Affidavit of Speed. So I decided to try that motion first. It worked!

BTW, no prosecutor appears.