Compact bowtie-shaped microstrip patch antennas with low cross-polarization and wideband harmonic suppression

A compact microstrip-fed bowtie-shaped circular ring slot antenna with a fundamental resonant frequency at 5.5 GHz for WLAN standards is initially studied. By introducing two bilateral triangles (BLT) slits symmetrically on either side of the radiator with a defected ground structure (DGS), wideband harmonic suppression (HMS) has been achieved. To get the dual-band i.e., lower band at 5.5 GHz and the upper band at 17.41 GHz for direct broadcast services (DBS) transmission satellite communication applications and additional suppress the harmonics excited by the insert-fed cut, a single inverted U-shaped slot (DGS) is integrated into the bowtieshaped patch. Bowtie-shaped single-band patch (BSBP) antenna measured impedance bandwidth (IBW) from 5.218-6.225 GHz (17.6%) and insert-fed bowtie-shaped dual-band monopole (IBDBM) antenna measured IBW from 5.254-6.168 GHz (16.61%) for the lower band and from 17.213-17.856 GHz (3.66%) for the upper band, a wideband HMS up to 3.17 f0 (f0 = fundamental resonant frequency) characteristics are achieved in both cases. The proposed antennas have a wideband HMS, compact size, and a significant reduction in cross polarization levels in E-plane radiation patterns. The design parameters are also predicted using a machine learning regression technique built on an artificial neural network and convolutional neural network algorithm.