Design and development of active integrated antenna for wireless lan system

Abstract

Wireless local area network (WLAN) applications nowadays has become more popular especially those operating in the 2.4 GHz ISM band. Newer laptops incorporated WiFi and Bluetooth technologies to connect to portable devices such as handsets and palmtop or to fixed devices such as printers. Nowadays, there are a lot of efforts on combining the WLAN, IEEE 802.11 a/b/g bands together. Even though IEEE 802.11a is not allowed in Malaysia (for aeronautical navigation and fixed satellite communication), this frequency spectrum might be available in the future. Such new designs either provide inadequate coverage of the frequency band or not suitable for integration in some portable devices. This thesis describes the design of the dual band microstrip antenna using scaling factor technique and inset feed with the integration of active devices. Different shapes of patches have been used to investigate any improvements that can be achieved. The antennas were designed to operate in the ISM band at 2.4 GHz and lower UNII band at 5.2 GHz. The dimensions of each single element of the microstrip antenna, at these operating frequencies were calculated using transmission line model. Two elements of inset fed antenna were used for each frequency band. The simulation process was done using the Agilent Advanced Design System and Microwave Office software. The passive antennas show comparable results to the typical monopole antenna used for access point. The active antenna gives a broader bandwidth than the passive type antenna.