New λ/2 microstrip bandpass filters using skew-symmetric feed structure

One type of magnetic coupling filter using skew-symmetric feed structure can create two transmission zeros in the upper stopband. The mixed coupling filter can generate one transmission zero lying on each side of the passband and the S₁₁, spectrum is slightly asymmetrically shaped in the vicinity of the center frequency. A two-pole hexagonal magnetic coupling filter using skew-symmetric feed structure is designed and fabricated. The filter has a fractional bandwidth of 3% at 2.45 GHz. The transmission zeros are obtained in the upper stopband at f₁ = 2.63 GHz and f₂ = 2.97 GHz.