Parasitic element coupling device enables high efficiency and smaller antenna design

Murata has revealed its new Parasitic Element Coupling Device. This state-of-the-art solution improves antenna efficiency by magnetically coupling the parasitic element with the antenna and is claimed to be the world's first solution designed for Wi-Fi 6E and Wi-Fi 7 products. For designers of smartphones, tablets, network routers, game consoles, and other compact electronics, it allows them to build more efficient antennas – an essential necessity for many modern space-constrained devices.

To develop products conforming to Wi-Fi 6E and Wi-Fi 7 standards, which use high-speed wireless communication, multiple high-performance antennas must be installed in electronic devices to enhance communication speed and quality. However, as the dimensions of heatsinks and batteries expand and processors become more advanced, the available space for mounting antennas tends to reduce.

Therefore, there is a need for smaller antennas. However, there is a technical limitation in that wide-band antennas' efficiency decreases when miniaturised. Thus, designers need a solution that accomplishes miniaturisation and high performance.

The company's solution is a parasitic element coupling device made with its multilayer technology as a four-terminal surface-mount component of just 1mm x 0.5mm x 0.35mm.

The parasitic element coupling device connects the feeding antenna to its parasitic elements more effectively than is feasible through free space. It acts as a tiny coupling device whose compact size allows strong coupling performance without utilising magnetic materials, which would be unsuitable at the targeted operating frequencies. At very low insertion loss, one side of the coupling device is connected between a device's RF circuitry and its main antenna. The other side is connected between the ground and the parasitic element. The resultant, more direct coupling allows the resonance characteristics of the parasitic element to be added to those of the feeding antenna. As a result, it enables more efficient operation across a broader frequency range or on multiple discrete bands.

The device helps combat that when an antenna is made smaller, the coupling between it and the parasitic elements decreases, while the coupling between the parasitic elements and the ground increases. By sustaining the coupling between the feeding antenna and parasitic element, the parasitic element coupling device allows designers to use miniaturised antenna design methods without impacting the communication band of efficiency.

The feeding antenna can cause an impedance mismatch when employed over a wide band, leading to a degradation in wireless performance. Also, when an antenna with a mismatched impedance is connected to a communication circuit utilising a long cable, the long cable can promote the impedance mismatch, causing larger insertion loss than expected and significantly reducing wireless communication performance. The device can improve antenna matching and decrease performance degradation in wireless communications, even when using long cables.