Laser Micromachining of Contactless RF Antenna Modules for Payment and Cards and Wearable Objects

The use of contactless payment methods for consumer transactions is becoming increasingly popular - 1.1 billion contactless transactions were made by Visa cardholders across Europe in the 12 months to July 2015 (€12.6 billion total value). Typically the contactless payment process uses a Radio Frequency (RF) enabled smartcard or a Near Field Communication (NFC) enabled smartphone. In order to ensure continued market acceptance and repeat usage the contactless operation must be robust, quick and efficient. This paper describes the development of an inductively coupled contactless smartcard utilising UV DPSS laser micromachining to fabricate the novel antenna structures from copper laminated epoxy tape. The design of the antenna modules was supported by device modelling using electromagnetic simulation software. Iterative laser ablated antenna prototypes were tested using a Vector Network Analyser to determine the optimum resonant frequency in the 13.56 MHz RFID range and a commercial automated RF test station to measure contactless functionality to EMVCO and ISO14443 standards. An antenna design toolkit was developed based on parameters such as kerf width, number of antenna loops, track width, pitch, antenna DC resistance, etc. The translation of the laser ablated antenna designs from smartcards to wearable objects, such as wristbands, is also presented.