I made a bash function to replace git archive command, :

function gitarch(){
    basedname=$(git rev-parse --show-toplevel)
    dname=$(basename $basedname)
    cd $basedname
    git archive --format=tar --prefix=${dname}/ HEAD | gzip > $fname
    cp $fname ${cwd}/
    cd $cwd

Writing this function in .bashrc file, I can create git archive with name projectname_date.tgz a little bit easier.

BTW, by typing :

$ type gitarch

you can see what is this function doing.