A design of amplifier using harmonic termination matching tuner and harmonic blocking bias line

In this paper, a new 3dB branch line hybrid using asymmetric defected ground structure (DGS) microstrip is proposed. The proposed branch line suppresses the 2nd and the 3rd harmonic component effectively. If transmission line having the arbitrary electrical length is connected at the through and the coupled port of DGS branch line hybrid, then DGS branch line hybrid is operated as impedance transforming tuner. Also a new DGS /spl lambda//4 bias line that can suppress high frequency harmonics as well as low frequency intermodulation is proposed. With harmonic termination tuner using the proposed hybrid and harmonic blocking bias line, the 2nd and the 3rd harmonic components of the fabricated amplifier that operated in IMT-2000 band were suppressed up 25dB and 27dB respectively. Harmonic load-pull setup of amplifier can be easily accomplished with proposed circuits.