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Many friends often buy GPRS spring antennas, which are not only cheap but also easy to weld and use. Do you know how to choose a GPRS spring antenna? Can you really use a GPRS spring antenna right after you buy it? Today we will evaluate three different GPRS spring antennas to see how they perform.
Before we start to evaluate these three antennas, let's first understand the composition of the GPRS frequency band: GPRS consists of two frequency bands, GSM900 and GSM1800, of which the center frequency of GSM900 is 920Mhz and the center frequency of GSM1800 is 1800Mhz.
Our evaluation method is to weld the antenna to the customer's real product, and then use a network analyzer to test the antenna's standing wave ratio to confirm the performance of the antenna. Friends who don't know what standing wave ratio is can read my previous article.
The following picture shows three GPRS spring antennas, of which GPRS Antenna 1 and GPRS Antenna 2 are finished products with good sales purchased on Taobao, and GPRS Antenna 3 is a GPRS spring antenna.
First, solder the GPRS antenna 1 to the product, as shown in the figure below (the product except the antenna is mosaiced to protect the privacy of the customer's product). We can see the standing wave ratio tested on the network analyzer. The center frequency standing wave ratio of GSM900 is 8.6, and the center frequency standing wave ratio of GSM1800 is 22.7. It can be said that the performance of this antenna is very poor. In simple terms, the smaller the vertical coordinate value of the corresponding frequency and the closer it is to 1, the better the performance.
Then solder GPRS antenna 2 to the product, as shown in the figure below (in order to protect the privacy of customers' products, the parts of the product except the antenna are mosaic processed). We can see the standing wave ratio tested on the network analyzer. The center frequency standing wave ratio of GSM900 is 7.2, and the center frequency standing wave ratio of GSM1800 is 14. Although the performance of this antenna is slightly better than that of GPRS antenna 1, it is still very unsatisfactory.
Then solder the GPRS antenna 3 into the product, as shown in the figure below (the product except the antenna is mosaiced to protect the privacy of the customer's product). We can see the standing wave ratio tested on the network analyzer. The center frequency standing wave ratio of GSM900 is 2.0, and the center frequency standing wave ratio of GSM1800 is 2.5. This antenna can meet the general performance standards of built-in antennas without any impedance matching debugging. It can be seen that it is a GPRS spring antenna with very good performance.
After the test comparison just now, it can be seen that you really can't just buy any GPRS spring antenna. The performance of the one you buy casually is often not good! Among the various GPRS spring antennas, GPRS Antenna 3, which is the GPRS spring antenna developed by our company, has the best performance. It can meet the design standards of the built-in antenna without any impedance matching and debugging.
In addition, this GPRS spring antenna is made of nickel-plated stainless steel, which has better oxidation resistance and corrosion resistance than copper.
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千斤顶