Adaptador de impedancias para antenas de 9 GHz de ancho de banda

This paper describes the design and analysis of an impedance matching network for spiral logarithmic (self-complementary) broadband antennas, able to operate in a frequency band of 1 GHz to 9 GHz. The proposed design is based on tapered microstrip lines which exhibit a progressive variation of its width by obtaining a gradual change in the impedance. Employing similar concepts over the ground plane, the transformation of a balanced to unbalanced system is achieved (Microstrip to Parallel Striplines Balun), which is necessary to connect the antenna to its feed. This design was optimized for low return loss and unity power transfer. The design was validated by simulation, yielding a return loss greater than 10 dB and an impedance matching between 50 Ω and 188 Ω, throughout the frequency range of interest.