PHP 全角半角どちらでもOKで、空白区切りで絞り込む検索

$keyword = mb_convert_kana($keyword, "s");
$keyword = trim(preg_replace('/\s+/', ' ', $keyword));
$words = explode(' ', $keyword);

foreach($words as $idx => $word){
    $word_h = mb_convert_kana($word, 'ak');
    $word_z = mb_convert_kana($word, 'AK');

    $options['conditions']['Hoge.hoge LIKE'] = "%{$word_h}%";
    .........
}