Sequentially rotated gap‐coupled variations of plus shape microstrip antennas for dual band circular polarized response

Abstract

Plus shape microstrip antenna for circular polarized response is proposed which gives VSWR and axial ratio bandwidth of 960 MHz (∼42%) and 101 MHz (4.97%), respectively. Using sequential rotation its gap‐coupled variations are proposed for dual band circular polarized response. With patches gap‐coupled along two co‐ordinate axis, an optimum dual band response showing axial ratio bandwidth of 97 MHz (4.3%) and 313 MHz (10.7%), with VSWR bandwidth of nearly 1000 MHz (>40%) is obtained.

Gap‐coupled designs of star shape microstrip antennas for dual band and wide band circular polarized response

“…Proximity fed design of plus shape MSA is shown in Figure A,B. The patch is fabricated on glass epoxy substrate ( ε r = 4.3, h = 0.16 cm, tan δ = 0.02), and it is suspended above the ground plane using an air gap ( h a ) of 1.3 cm . For implementing low cost design, glass epoxy substrate in suspended variation is selected here.…”

“…The MSA is fed using proximity feed which is placed at thickness of “ h s ” above the ground plane. For total substrate thickness ( h + h a ) of 1.46 cm (~0.1 λ g ) longer length in plus shape MSA “ l 1 ” is optimized for TM 01 mode frequency of around 2000 MHz . Patch width “ w s ” is taken to be 0.27 times the length .…”

“…For total substrate thickness ( h + h a ) of 1.46 cm (~0.1 λ g ) longer length in plus shape MSA “ l 1 ” is optimized for TM 01 mode frequency of around 2000 MHz . Patch width “ w s ” is taken to be 0.27 times the length . Optimum CP response in plus shape MSA is obtained for length ratio ( l 2 / l 1 ) of 0.853.…”

“…Optimum CP response in plus shape MSA is obtained for length ratio ( l 2 / l 1 ) of 0.853. It gives VSWR and AR BW of 940 MHz (>40%) and 101 MHz (4.97%), respectively . Further star shape MSA is realized by tapering patch width along the length, as shown in Figure A.…”

“…First design of plus shape MSA and equivalent star shape MSA is discussed. They yield AR BW of 4.97% and 5.41%, respectively in 2000 MHz frequency range . The resonant length formulation for star shape patch is presented.…”