Triple band circularly polarized printed crossed dipole antenna employing interdigital capacitors

A novel triple-band circularly polarized printed crossed dipole antenna is proposed. Circular polarization (CP) in the antenna is achieved by feeding the orthogonal dipole arms with 90o phase difference using vacant quarter printed ring. Loading of the dipole arms with interdigital capacitor (IDC) of suitable parameters provides the triple band CP operation. The effects of variation in the parameters like finger length, vacant ring radius and vacant ring width have been studied in details. The CP bands can be tuned by varying the IDC parameters, instead of changing the main radiator dimensions. The proposed antenna can be used as surface mounted antenna for GPS/GSM/UMTS applications.