Four Slot Microstrip Antennas For Circular Polarization

Ultra high frequency (UHF) bands using radio frequency identification (RFID) systems are widely used in many applications because of their wide reading range and fast reading speed [1]. Commercial use of UHF RFID systems in logistics and supply chain management has become very widespread and the importance of compact handheld reader units is getting more and more important RFID technology has become increasingly important for short range wireless communications and information (tags) Use the. Please use RF reading.

Microstrip antennas are small in size consistent with planar and nonplanar surfaces and are easily and cheaply constructed using modern printed circuit technology. Microstrip antennas have very flexible characteristics with respect to polarization, resonance frequency, impedance and radiation pattern. It is also used to increase bandwidth. They include a ground plane to which the substrate is attached and to which the radiating patch is attached. Typically, the ground plane and the dielectric substrate have equal length and width. The microstrip antenna is represented by the width, the length, and the height of the dielectric substrate, and the dielectric substrate is sandwiched between the ground plane and the radiating patch.

Microstrip patch antennas are classified as printed antennas. The radiating patch is usually printed on a grounded substrate powered via a transmission line or a coaxial cable. The patch can be of any shape and size, ie circular, square, triangular or rectangular. Microstrip patch antennas are best known among all printed antennas, ie dipole, slot, and tapered slot antennas. They are small in size, light in weight, and have low power consumption. However, they have less bandwidth and lower gain. They are easy to integrate and have good radiation control and low manufacturing costs. Many techniques are used to introduce slots and slits etc. to increase bandwidth. They are used commercially for radar, wireless communications, satellite and mobile equipment.

Microstrip antennas are one of the most widely used antennas in the microwave frequency band and are usually used in the millimeter wave frequency band (less than about 1 GHz, microstrip antenna size is usually too large to be practical It is not a point). The microstrip patch antenna consists of a metallic metal patch on a grounded dielectric substrate of thickness h with relative permittivity and magnetic permeability μrr and μr. As shown in Fig. 5 (a) (normal μr) = 1). As shown in FIGS. 5 (b) and 1.5 (c), the metal patches can be of different shapes, most commonly rectangular and circular.