Patent ID: 6924768

Claim:
A method for designing a printed antenna structure for transmission of a spectrum of electromagnetic waves having a wavelength λ g at the center frequency f 0 , wherein λ g = 1 ɛ re * c f 0 , c is the speed of light, f 0 is the center frequency of electromagnetic waves, and ∈ re is the equivalent dielectric constant, said method comprising: assuming an open transmission line for transmission of the electromagnetic waves with the wavelength λ g having a length L, and L=λ g /4, wherein the input impedance of the open transmission line is jX t , Z 0 is the characteristic impedance of the transmission line and jX t =−jZ 0 cot(2πL/λ g ); preparing the printed antenna structure, said printed antenna structure comprising a primary radiating element and a tuning element electrically connected to one end of the primary radiating element, said primary radiating element having an overall length of L 2 , said tuning element comprising two stubs, each one of the stubs having a length of L 1 and including a free end spaced apart from each other and a fixed end connected to the primary radiating element, wherein the overall input impedance of the combination of the primary radiating element and the tuning element is also equal to jX t ; assuming ⁢ ⁢ f ⁡ ( β ⁢ ⁢ L1 ) = β ⁢ ⁢ L1 + β ⁢ ⁢ L2 = β ⁢ ⁢ L1 + π 2 - cot - 1 ⁡ ( cot ⁢ ⁢ β ⁢ ⁢ L1 2 ) , ⁢ wherein ⁢ ⁢ β = 2 ⁢ π λ g ; and calculating the values of L 1 and L 2 for obtaining a minimum value of f(βL 1 ), and using the calculated L 1 and L 2 to design the printed antenna structure.