Leaders of an anti-tax group trying to overthrow the Fairfax County Board of Supervisors and limit annual real estate tax increases have abandoned their effort to hold a referendum on the county's form of government this year.

Marcia Dykes, who with her husband, Frederick T. Dykes, founded Citizens for Sensible Taxation, said yesterday that the group may try to force a referendum in November 1991, when local elections are scheduled.

The Dykeses originally had hoped to force a special election on the county's form of government this summer.

They claimed that if voters approved changing the county's government from the current urban county executive form to the county manager form, it would require the sitting supervisors to stand for reelection this fall, a year before their regular four-year terms expire.

Ultimately, the group is seeking state and local legislation limiting increases in real estate tax bills to 5 percent a year, which would require an amendment to the state Constitution.

It also seeks to freeze property taxes for people more than 65 years old.

A Circuit Court judge ruled two months ago that petitions demanding a special referendum this summer fell 778 signatures short of the 40,589 needed to compel one.

As a fallback option, the Dykeses were considering seeking a referendum on the form of government for this November's ballot.

Although they technically had until Sept. 6 to succeed, Marcia Dykes said that there was not enough time to meet various legal requirements, such as signature verification.

"Every time we did anything, the county intervened," she said. "We haven't been outmaneuvered, we've been hauled into court."

Dykes said the executive board of her group will decide whether to begin a 1991 referendum drive.