Quality Control

Antenna quality control

From single polarization antenna, dual polarization antenna to smart antenna, MIMO antenna and large-scale array antenna, mobile communication antenna has undergone great changes. As a sensing organ of mobile communication network, its position in the network is becoming more and more complex, and it is more and more important. For example, more than 40% of network failures are caused by antenna system. The quality of antenna system will lead to poor coverage performance or interference. As a complex passive product, antenna is difficult to monitor in the network. Antenna system is problematic The performance of the network is various, such as the network coverage performance is obviously decreased, intermodulation interference is more and more serious, and VSWR worsens when the air humidity is too high. It is urgent to improve the antenna quality.

1. Stability - the ability of a product to maintain its characteristics constant over time, usually the ability of a product to remain unchanged over time.
The stability and reliability of the product are inseparable. The reliability of antenna performance is judged by the coincidence degree of index curves before and after reliability test.

(1) Radiation parameters are not sensitive to process and circuit, while circuit parameters are sensitive to circuit and process. In production process, especially many times of debugging, it is easy to influence circuit parameters;

(2) Among the circuit parameters, the intermodulation is too small, and it is not suitable for statistical evaluation because of its high sensitivity to test methods, testing equipment and environment;

(3) The circuit parameters are low in requirement for the test site, and can be tested on site. Radiation parameters require high reflection and shielding characteristics of the test site, and can not be tested on site.

Therefore, it is suggested to select the ratio of standing wave and isolation degree of circuit parameters as the stability characterization parameters of antenna performance.

2. Reliability - generally, the reliability of a product refers to the ability or possibility of components, products, systems to perform specified functions without failure in a certain period of time and under certain conditions.
Reliability of products can be evaluated by reliability, inefficiency, average fault free interval, etc. Environmental reliability refers to the ability of products to complete the specified functions under the specified conditions and within the specified time. In the process of design and application, the products are constantly subjected to the influence of their own and external climate and mechanical environment, but still need to be able to work normally, which requires the verification of them with test equipment. Reliability includes three factors: durability, maintainability and design reliability. The reliability of design is the key to determine the quality of the product. In the design, the usability and operability of the product must be fully considered, which is the requirement of an excellent antenna product designer. The reliability test of antenna products is an important means to investigate, analyze and evaluate the reliability of antenna products. It includes high and low temperature test, rain test, vibration test, impact test, collision test, vehicle transportation test, wind load test, ice taking test and power test. The reliability of antenna structure can be tested by environmental test.

3. Consistency - refers to the consistency of the parameters of the same antenna product.

In a word, antenna belongs to the passive product with broadband and low Q value, and will not be restored after the material structure is damaged during reliability test. The frequency change caused by thermal expansion and contraction of materials during high and low temperature test is ignored. The change of test index after comparison test is enough to reflect the stability of electrical performance index, and it is not necessary to test the index during reliability test. The intermodulation index of antenna is sensitive to the manufacturing process and structural stability. Dynamic test can be adopted to verify the product stability indirectly. The reliability, stability and consistency of antenna have important influence on mobile communication network. It is important to measure and control these performances before antenna products enter the network. The key is to identify key parameters and sensitivity in the process of antenna design to control the risks in large-scale production. Risk points can be realized by the parameter analysis of full wave simulation, but many parameters are often coupled with each other, which makes it difficult to identify their own independent sensitivity. This difficulty can be solved by feature model analysis. We have done comparative study, and the sensitive parameters in the feature mode gap are consistent with the sensitivity of the parameters in the real full wave analysis and test. The information obtained from feature model analysis can help to identify key information, so as to improve machining accuracy or protect necessary in key places, so as to ensure consistency and stability.