ABFT

RF antennas are an important link in most modern communication systems, and antenna technologies such as planar inverted F antennas (PIFA) and active integrated antennas (AIA) have been widely used in radio frequency communication systems. PIFA antennas and AIA antennas are often referred to as ABFT (active balanced folded dipole) antennas. An ABFT antenna makes use of dual pole topology to improve the bandwidth and gain of the antenna. It can provide an extended operating frequency range and high performance at multiple frequency bands.

The application field of an ABFT antenna include mobile telephony, mobile data, and wireless networking. It is often used in cellular phones, wireless network hubs, and wireless modems. It can also be used in a variety of wireless communication systems, including but not limited to, GSM, CDMA, Wireless Local Area Network (WLAN), and Bluetooth. ABFT antennas can also be used in point-to-multipoint systems, microwave systems, and satellite systems.

The working principle of an ABFT antenna is based on the principle of the balanced folded dipole antenna. The antenna consists of dual dipole elements that are placed in a folded configuration. These elements are connected to an active matching circuit, which is responsible for matching the impedance of the antenna to the input impedance of the transmitter. The active matching circuit is also responsible for controlling the bandwidth and gain of the antenna.

The folded dipole is balanced in two ways: firstly, the dipole elements are balanced electrically, and secondly the dipole elements are balanced in terms of radiation pattern. This ensures that the antenna is able to provide an omnidirectional radiation pattern and a broad bandwidth. Furthermore, the active matching circuit is responsible for controlling the return loss of the antenna, thereby improving the efficiency of the antenna.

In addition to the active matching circuit, an ABFT antenna also includes a tracking circuit which enables the antenna to automatically adjust its radiation pattern to compensate for changes in the environment. This ensures that the antenna is able to maintain its maximum radiation efficiency in different environments. Furthermore, the tracking circuit also helps reduce the return loss of the antenna, thereby increasing its efficiency.

An ABFT antenna offers numerous advantages over other antenna types, such as high performance in multi-frequency bands, extended operating frequency ranges, high efficiency, and low profile design. Its active components provide further improvements in terms of gain, bandwidth, and flexibility. With its omnidirectional radiation pattern, the ABFT antenna is well suited for a variety of wireless communication applications.