X-Band Hybrid-Integrated VCOs with High Tuning Linearity

This paper describes a X-band Gunn diode VCO using GaAs abrupt varactor, its electronic tuning linearity is improved by multi-section reactance compensation. The performence of this VCO has been acheived as following: linearity of 3% within 1000MHz bandwidth, 2% within 900MHz, O.8% within 600MHz, electronic tuning slope ratio less than 1.2 within 600MHz. The principle of improving VCO linearity by reactance compensation is discussed here, some formulas is derived, and the advantage of multi-section over single-section is described. The topology of practical circuit of VCO with multi-section compensation is given.