Parasitic Element Coupling Device is a coupler that facilitates broadband and miniaturization of antenna characteristics. For antennas that require a wider frequency bandwidth, such as Wi Fi 6E, Wi Fi 7, and cellular networks, antenna miniaturization can be achieved through broadband and improved antenna efficiency.
Product principle and structure:
Parasitic antenna coupler is a coupler that can further broadband and improve antenna efficiency by strongly coupling the feeding antenna and parasitic elements (parasitic antenna) with this coupler. Therefore, even small antennas that are difficult to adapt to parasitic components can achieve good antenna characteristics by mounting this coupler.
Schematic diagram and effect of parasitic antenna coupler (broadband and improving antenna efficiency)
Murata achieved strong electromagnetic coupling without the use of magnetic materials by using our company's proprietary multi-layer technology to closely configure the transformer coils. Thus, this coupler was developed to improve antenna characteristics and contribute to miniaturization.
The advantages of parasitic antenna couplers:
Advantage 1: Broadband antenna and improved antenna efficiency
By using parasitic antenna couplers for the antenna section, broadband can be achieved. The following figure compares antenna characteristics (return loss) and antenna efficiency through simulation when using parasitic antenna couplers and when not in use. From the figure, it can be seen that by strong electromagnetic coupling between parasitic components and feeding antennas, increasing the antenna resonance of parasitic components can achieve broadband and improve antenna efficiency.
The broadband return loss caused by parasitic antenna couplers and the effect of improving antenna efficiency (simulation)
Advantage 2: miniaturization of antennas
The effect of improving antenna efficiency through parasitic antenna couplers can achieve miniaturization of the antenna part. Generally speaking, if the feeding antenna and parasitic components are placed side by side in weak electromagnetic coupling to miniaturize the antenna, the coupling between parasitic components and GND becomes stronger, and the coupling with the feeding antenna further weakens. As a result, the function of the antenna as a parasitic component is reduced, and the efficiency of the antenna deteriorates. Because parasitic antenna couplers strongly electromagnetic couple parasitic components with feeding antennas, even small antennas are expected to achieve good antenna efficiency.
The miniaturization of the antenna section and the effect of parasitic antenna couplers on improving antenna efficiency (simulation)
Advantage 3: Reduce the impact of cable losses
By using parasitic antenna couplers to couple parasitic components strongly to the antenna, matching can be improved. To prevent multiple reflections between the antenna and module. It can reduce the impact of insertion loss when using long cables.
为了验证这一效果，我们做了如下的评估测试：
Set 1: 700mm Coaxial cable
The evaluation results of the two sets of settings are as follows:
The evaluation results show that using parasitic antenna couplers can significantly reduce the impact of insertion loss when using long cables, especially at 5GHz.
Murata Productions has a product lineup for various frequency bands:
| Part Number | Type | insertion loss | DCR(Max) | |
| Test frequency | IL(dB) | (Ω) | ||
| LXPC15AHA1-001 | For middle/High Band | 1.7GHz | 0.1 | 0.2 |
| LXPC15AHR1-002 | For middle/High Band(Mirror type of-001) | |||
| LXPC15ALA1-003 | For low Band | 1.7GHz | 0.1 | 0.4 |
| LXPC15ALR1-005 |
For low Band(Mirror type of-003) |
|||
| LXPC15AUA1-008 | For Sub6G Band | 3.3GHz | 0.2 | 0.3 |
| LXPC15AUR1-009 | For Sub6G Band(Mirror type of-008) | |||
| LXPC15AWA1-012 | For Wi-Fi 6G | 6GHz | 0.35 | 0.3 |
| LXPC15AWr1-013 | For Wi-Fi 6G(Mirror type of-012) | |||
The measurement is made when Port3 and Port4 are open and Port1 and Port2 are connected, which compensates for the reflection loss of Port2.
Application case:
Parasitic antenna couplers can be used for various products carrying antennas:
Laptop computer
Smartphones/mobile phones
Tablets
XR (AR, VR, etc.)
DSC (Digital Camera)
Game (portable gaming console)
television
Wireless router
The following diagram is the circuit diagram of a smartphone using a frame antenna. Parasitic components are configured on the substrate and broadband is achieved through coupling with parasitic couplers.
ng" alt="" width="600" height="380" />
