A VCO with Harmonic Suppressed and Output Power Improved Using Defected Ground Structure. (2003)

• Record Type: Journal Article
• Authors: Liu, Haiwen; Sun, Xiaowei; Li, Zhengfan
• Is Part Of: Active and passive electronic components. Volume 26:Number 4(2003)
• Page Start: 205
• Page End: 211
• Publication Date: 2003
• Subjects: Electronics -- Periodicals; Passive components -- Periodicals; Electronic apparatus and appliances -- Periodicals; 621.381505
• DOI: 10.1080/0882751031000116106
• Languages: English
• ISSNs: 0882-7516

Abstract

Abstract : In this paper, a novel defected ground structure (DGS) is proposed for suppressing harmonic and increasing the output power of a voltage-controlled oscillator (VCO) in microwave circuits. The DGS is formed with connecting in parallel two periodic structures which have different center frequencies (in a ratio of 2:3) of the stopband and provides the bandgap characteristic in certain frequency bands. Simulated and experimental results show that the microstrip line with DGS has a wide low-pass band for the fundamental frequency and a stopband for the second harmonic with good performance. To evaluate the effects of DGS on microwave VCOs, two GaAs field-effect transistor (FET) VCOs have been designed and fabricated. One of them has a 50Ω microstrip line with DGS at the output section, while the other has only a 50Ω straight line. Measured results show that DGS suppresses the second harmonic more than− 20 dBm at the output and yields improved output power by3 − 5 % .