Why is balanced filter selected based on IC?

ICs from different manufacturers have their own characteristic impedance at RF input port. One of the functions of balanced filter is to match impedance and thus the impedance needs to be checked when selecting a balanced filter.

Can LTCC filter substitute SAW filter?

SAW filter (surface acoustic wave filter) is a key component of radio frequency circuit. SAW filter works great at out-of-bandwidth attenuation and narrow bandwidths with steep transition edges. In addition, its size is smaller. However, for those SAW filters used at higher frequencies, the production gets more complex, resulting in higher prices.

The advantages of multilayer chip LC filter are good performance for wide bandwidth, low insertion loss and low price. It is a good choice especially for Bluetooth application.

What are the popular dimensions of multilayer chip antenna in application?

The current popular size of multilayer chip antenna is 3216 and 5020. The trend of dimension is miniaturization and 2012 size will be expected to come to the market in the future.

Why is the gain of your Bluetooth antenna has both positive and negative values?

The antenna gain is the ability to transmit or receive signals. The greater the gain, the better the ability. The numerical value is not a vector so both negative and positive exist. And it is sure positive gain will make better performance than negative gain.

Any advice for the layout of the multilayer chip antenna?

Try to avoid metal, screen, screws and other devices, because they would cause unexpected effects to antenna radiation. Keep the line of matching circuit as short as possible. Keep matching circuit and antenna on the same PCB plane.

Why is the center frequency of Sunlord Bluetooth antenna higher than 2.45GHz? Why not the same as other manufacturers?

The spec center frequency of Sunlord Bluetooth antenna is measured based on the test board of Sunlord and the environmental parameters are not included. As other manufacturers are using different test boards, their spec center frequencies vary. Generally, the field center frequency of chip antenna after soldering on PCB is not the same as the spec value due to the effect of metal material such as LCD panel, shell, etc.

The field center frequency always shifts toward lower value. It is easier to adjust to 2.45GHz from higher center frequency than from lower center frequency when designing matching circuit. That is why the spec center frequency of Sunlord Bluetooth antenna is higher than 2.45GHz.

What’s the application for Bluetooth antenna?

Bluetooth antenna can be used in Bluetooth, WIFI and other applications related with ISB band of 2.4GHz frequency. For example, Bluetooth phones, Bluetooth headsets, wireless mice, wireless speakers and some Bluetooth modules.

What are the pros and cons of multilayer chip antenna compared with other antennas?

With the continuous requirement of multifunctional modules, the structure of electronic equipments becomes more complex and the space for Bluetooth antenna keeps getting smaller.

The outstanding advantage of multilayer chip antenna compared with other antennas such as ceramic antenna PIFA and PCB antenna is the smaller space needed to take up. And another feature is the convenient and fast design and adjustment for matching circuit.

However the price of multilayer chip antenna is a little higher than PCB antenna. Based on performance to price ratio, we recommend multilayer chip antenna to be applied in small portable electronic equipments.