How to add a textfield in form with out model class in YII?

I need to add a text field in YII form in which i am not specify any model class name. But I need to process that value in the action method inside the controller class.

ie

I need to add a text field as

<div class="row">
    <input type="text" name="test" id="test" >
</div>

I add text field as

<?php echo $form->textField($model['groupModel'],'group_name',array('size'=>60,'maxlength'=>128)); ?>

But i do't want to specify any model name with the new text field.. Thanks in advance...