DESIGN AND DEVELOPMENT OF COMPACT MICROSTRIP ANTENNAS FOR PORTABLE DEVICE APPLICATIONS

During the last decade, wireless communication system developments have been a major motivator of compact antenna research, most particularly for portable device applications. This paper addresses to a development procedure of designing compact antennas. By a careful observation at the current distribution and folding of slots after calculating the resonating slot length, the compactness of microstrip antenna can be achieved. Two compact slot antennas, namely hollow central annular slot antenna ( HCASA) and spiral slot antenna (SSA) are designed and prototyped for validation, where the experimental result agrees well the simulation. The overall volume of these antennas are respectively 0.11 lambda(o) x0.11 lambda(o) x0.005 lambda(o) and 0.08 lambda(o) x0.08 lambda(o) x0.005 lambda(o) where. lambda(o) is the free space operating wavelength, that concludes the reduction of 75 and 86.2% of antenna volume comparing that of an ordinary annular slot antenna operating at the same frequency.