Design of Microstrip Antenna conformable to both planar and cylindrical surfaces for Aircraft Systems

Abstract

This thesis deals with design of microstrip antennas conformable to both planar and cylindrical surfaces for aircraft systems. A symmetrical 2×2 microstrip antenna array at newline10 GHz is fabricated to validate the results. An optimum inter-element spacing of 0.55 and#955; in both E and H plane for frequency range of the array has been arrived at. In easymmetrical 2×3 array configurations, results correspond to 0.55 and#955; and 0.5 and#955; for E and H plane respectively and vice versa. Design of the multidielectric layer planar antennas using an algorithm developed by the author provides fabricated antenna operating close to the designed frequency. Accuracy achieved in both simulation and fabricated antenna results using conformal mapping technique showed improved accuracy in performance. The antenna losses in the design of multidielectric microstrip patch antenna are contained through the control of the quality factors. While ensuring the desired radiation pattern, the design provides an improved bandwidth of the fabricated patch antenna. Changes in characteristics of the antenna to achieve frequency agility are shown in a conformably mapped and fabricated microstrip antenna. Author proposes frequency agility of the multidielectric microstrip antenna by replacement of cover layer with materials of different permittivity. Wheelers transformation technique transforms conformal cylindrical patch antenna to a planar patch. Two element microstrip patch antenna array with a corporate feeding network on a cylindrical surface is transformed using conformal mapping technique. Designed antenna array resonates at 10 GHz, however the resonating frequency is seen changing due to mutual coupling and at 0.6 and#955; inter element spacing it is resonating closest to the designed frequency. Four element transformed microstrip patch antenna has been considered for comparison. The rigour of analysis of conformal antenna on cylindrical surface is overcome with successful results by analyzing transformed antenna in planar domain.