Effects of RF passive component applications on wireless communications

In recent years, for the purpose of saving costs and reducing duplication of construction, many indoor distribution systems have adopted the model of a multi-combined system that shares a room with other sub-systems. This means that multi-system and multi-band signals are fused within common combination platforms and shared indoor distribution systems to achieve multi-band, multi-system, one-way, or two-way transmission.

The benefit is to reduce duplication of infrastructure and save space. However, the problems caused by such indoor distribution systems are becoming more prominent. Multi-system coexistence inevitably introduces inter-system interference. In particular, the operating frequency bands are similar, and the interval bands are small, the spurious emission and PIM between different systems are also affected.

In this case, a good quality passive device can mitigate the effects of this interference. A poor-quality RF passive device itself will also lead to the decline of some network indicators, and high-quality devices will have a positive effect on network quality, to inhibit the occurrence of spurious emissions, interference, and isolation.

The main types of interference in wireless networks are divided into in-system interference and inter-system interference. In-system interference refers to the strays of the transmit band, which fall into the interference of the system itself caused by the receiving band. Inter-system interference is mainly spurious emissions, receiver isolation, and PIM interference.

Depending on a common network and testing condition, passive devices are a key factor affecting common networks.

Key factors of making a good passive component include:

1. Isolation

Poor isolation will cause interference between systems, conduction of stray and multi-carrier PIM, then interference with the terminal upstream signal.


In the case VSWR of passive components is relatively large, the reflected signal becomes larger, in extreme cases the base station will be alerted for damage to the RF elements and amplifiers.

3. Rejections in out-of-band

Poor out-of-band rejection will increase inter-system interference, but good out-of-band inhibition ability, and good port isolation will help reduce interference between systems.

4. PIM - passive Intermodulation

Larger PIM products fall into the upstream band will cause deterioration of receiver performance.

5. Power capacity

In the case of multi-carrier, high power output, and high peak ratio signal, insufficient power capacity will lead to high system load. This causes the network quality to drop seriously, which in turn causes arcing and fire conditions. In severe cases, it is possible to break or burn the equipment, causing the base station network to collapse.

6. Device processing process and materials

Material and processing processes are not closed, directly leading to the device's parameter performance degradation, while the device durability and environmental adaptability are greatly reduced.

In addition to the key factors above, there are some general factors as follows:

1. Insertion loss

Insertion loss over-assembly makes the signal lose more energy on the link affecting the coverage, while increasing the direct station will introduce new interference, and simply improve the base station transmission power is not environmentally friendly, and beyond the amplifier line optimal linear operating range when the transmitter signal quality will deteriorate, will affect the expected realization of indoor distribution design.

2. In-band fluctuations

Large fluctuations will lead to a poor flatness of the in-band signal, when there are multiple carriers that will cover the impact, and affect the expected implementation of indoor distribution design.

Therefore, passive components play a key role in the construction of ae communication network base station.

Jingxin focuses on customizing the passive components needed for customers, whether from the initial evaluation, mid-term design advice, or late mass production, we adhere to the quality first, to provide services to customers around the world.

RF passive components

Post time: Oct-13-2021