Ultra-Low Power Active Integrated Antenna using Tunnel Diode for Tracking Application.

Modern tracking systems require the combination of transmitters and antenna parts into a compact and single package to minimize dimensions. In order to have a stable and efficient platform, each component should be designed with high accuracy to be compatible in the required frequency bandwidth. Today, designing small tracking systems is a big challenge in commercial navigation systems. These systems can be used to help shop store managers to increase safety. Moreover, RFID systems can be used for rescue and cellular operator applications to find unknown targets. All of these systems need special antennas and transmitters and the antennas and active parts should have low profile, wideband to cover most of the RF frequency bands (HF, VHF, UHF and S bands) and the capability to send enough RF power. Most targets and receivers do not have enough space for their antennas and RF active circuits; therefore the primary challenge for transceiver designers is proposing small antennas and active blocks. Most tracking systems typically operate in the UHF band where microstrip antennas are good candidates to be used for portable applications (9). A good candidate is the bow tie microstrip antenna. A bow tie antennas can be fed by coaxial connectors, balanced microstrip lines or unbalanced microstrip lines (10; 11; 12; 13). The best method is using a balanced line to prevent having the balun to minimize overall size and RF loss. The primary challenge of using tow tie antennas is their size at low frequencies (UHF band). Therefore, we need to design a smaller size antenna with a matching circuit. The matching circuit should compensate capacitive behavior of the antenna at the lower antenna resonant frequency.