Technique that can be developed to detect UFOs

The instrument should not ony be capable upto lower rf range but also capable for detecting lowest and highest frequency that is existed in space.Any possibilities should be found that ray can be from dark matter which is spreaded in space so this type of ray will not feel any boundry in space as the other radio waves find.With this type of ray alien can appear any where on earth and we can not detect them with our instruments that are made to detect rf waves.