, the production process does not require structural design engineers participation, in accordance with the current market conditions, generally priced at 800 yuan left the mobile phone sales to more than 5K, the customer can recover the cost, and then there are more orders, customers have have to make. GPS signal can be jammed with help of cell phone jammer . Such as the MD thin, so the circuit is also thin and only work. HW will be required MD place the antenna area is relatively large, and the distance of the battery should be far enough, HW will also require ID should not be placed near the antenna metal parts. One can imagine a built-in antenna design mobile phone, its manufacturing cost than the design of an external antenna on the phone to your 20-25%, the main factors is the antenna design, material requirements and circuit design and The manufacturing costs are higher on average some. Usually architect (MD) and the Industrial Designers (ID), there will be controversy, MD said that ID is a painter, painting some of the things we usually do not. The emission power of cell phone jammer  will be greatly reduced.