Analysis and Design of Gap-Coupled Annular Ring Microstrip Antenna

Table 3

Peak value of input impedance, resonance frequency for upper and lower band for different gap lengths.

Feed point ↓	c  =  3.001 cm				c  =  3.101 cm				c  =  3.201 cm
Gap length 𝑃lower	𝑃upper (ohms)	𝐹lower (ohms)	𝐹upper (GHz)	𝑃lower (GHz)	𝑃upper (ohms)	𝐹lower (ohms)	𝐹upper (GHz)	𝑃lower (GHz)	𝑃upper (ohms)	𝐹lower (ohms)	𝐹upper (GHz)	𝐸𝜃 (GHz)
S  =  0.09 cm	35.39	74.31	1.710	1.899	34.81	72.41	1.736	1.9337	33.61	65.33	1.770	1.9771
S  =  0.10 cm	43.58	73.93	1.744	1.899	43.62	72.06	1.771	1.9338	42.35	64.16	1.806	1.9771
S  =  0.11 cm	53.05	73.30	1.778	1.900	55.90	71.74	1.806	1.9343	53.20	65.49	1.842	1.9774