How to select a chip antenna in the RF circuit?

For applications where PCB size is very small, the chip antenna is not a good way (below). They are ready-made antennas, the occupied PCB space is minimal, and can provide better performance. However, the chip antenna increases the material (BOM) and assembly costs. Because these things need to order and assemble external components. Typically, the price of chip antennas is approximately 10-50 cents, and the specific price depends on dimensions and performance. When using the chip antenna, another key factor should also be considered: it is affected by the radiation grounding area. Therefore, it is necessary to follow the recommendations of the manufacturer's docking area. Unlike the PCB antenna, the chip antenna cannot be adjusted by changing the length of the antenna. In addition, a matching network can be adjusted to adjust the antenna, thereby adding more cost of material. Cypus only recommends using chip antennas in a particular application that requires PCB space, for such applications, Cypress recommends using the following Johnson technology chip antenna: 1. 2450T18B100E 2. 2450AT42B100E The 2450At18b100e size is 63 mil x126 mil. 2450T42B100E size larger: 118 MILS × 196 MILS, but provides better RF performance. The Cypress BLE module CYBLE-022001-00 uses a 2450At18b100E antenna and has been widely measured for RF performance and pre-decisive testing. Chip antennas require some layout guidance to achieve optimal radio frequency performance. The following is the main considerations for chip antenna placement, layout and radio frequency performance: 1. The ground gap around the antenna 2. The location of the antenna best radiation 3. Precautions for antenna feeder 4. Matching network with antenna bandwidth extension 2450AT42B100E chip antenna of Johnson Technology This layout also shows a 50 Ω feed line and a component that matches thereto. The width of the feed line depends on the thickness of the board. The accurate circuit board thickness is specified in Table 4. Johanson 24AT42B100E Antenna Layout Guide The performance of the chip antenna is determined by the ground plane. In general, they require more grounding area and larger space. As shown in the figure above, for the antenna of 2450 value42b100e, the minimum ground distance is 0.8 mm. When the spacing is 2-3 mm, the observed echo loss will be more obvious. The chip antenna is not necessarily strictly equal. Radiation has some preferred direction. According to the GND pitch and plastic accessories, the maximum direction of radiation is different. For the common radiation directions of Chip antenna (2450AT42B100E) of Johnson Technology, please refer to the figure below. Radiation map of chip antenna Cypras only recommends using chip antennas to use specific applications that require PCB space, for example: NANO Bluetooth transceiver or ultra-small module. The Johansson antenna is characterized by Cypress's RF performance and predecessibility for Cypress EZ-BLE modules. You can use Murata, Other chip antennas provided by suppliers such as Vishay, Pulse and Taoglas.7.