A novel compact six-port circuit with harmonics suppression

A novel small-size harmonics-suppression six-port circuit based on a compact coupled-line power divider and three compact couplers with harmonic suppression is proposed and fabricated. This proposed circuit area is reduced 65% compared to the conventional one. Within the operating frequency band (f₀=840 MHz), the measured return loss (|S₁₁| to |S₆₆|) are larger than 20 dB, the insertion loss (|S₃₂| to |S₆₂|) are between 6 dB and 7.5 dB, and the phase imbalances are less than 6 degree. The measured harmonics suppression of 2f₀ and 3f₀ are larger than 30 dB and 6O dB, respectively.