Design of a Novel Wideband Loop Antenna with Parasitic Resonators

A novel coax-fed wideband loop antenna loaded with rectangular patches and U-shaped elements is presented and studied. By inserting a pair of rectangular patches inside the strip loops and employing a pair of U-shaped elements as the parasitic resonators, two additional resonances are excited and a good performance of bandwidth enhancement can be obtained. The measured results indicate that the impedance bandwidth (VSWR≤2) is about 87.1% from 1.58 to 4.02GHz, which covers the required operating bands of DCS1800 (1710–1880MHz), PCS1900 (1850–1990 MHz), UMTS2100 (1920– 2170MHz), WLAN2400 (2400–2484 MHz), LTE2300/2500 (2300– 2690MHz) and WiMAX3500 (3300–3690MHz). In addition, good radiation characteristics such as symmetrical radiation pattern, moderate peak gain, low back radiation, and low cross-polarization are observed over the entire operating band.