Abstract-In this paper, a novel compact band pass filter (BPF) is proposed for Global Positioning System (GPS) receivers. The proposed BPF configuration is composed of a low pass filter (LPF) section formed by the coupled line transformer connected with a radial stub and two short circuited stubs embedded within the 50 Ω microstrip line connecting the input/output (I/O) port of LPF. The lumped equivalent model of proposed BPF is also presented and analyzed. Simulation as well as experimental results shows very good in-band (pass-band) and out-of-band (≈ 7f c (centre frequency)) characteristics. The 3 dB fractional bandwidth (FBW) is 3.2% of f c , thus satisfying the GPS receiver requirement and the minimum insertion loss (IL) in pass-band is 1.28 dB.

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Abstract. In SST-1, 42GHz ECRH system has been commissioned to carry out breakdown and heating experiments at 0.75T and 1.5T operating toroidal magnetic fields. The 42GHz ECRH system consists of high power microwave source Gyrotron capable to deliver 500kW microwave power for 500ms duration, approximately 20 meter long transmission line and a mirror based launcher. The ECRH power in fundamental O-mode & second harmonic X-mode is launched from low field side (radial port) of the tokamak. At 0.75T operation, approximately 300 kW ECH power is launched in second harmonic X-mode and successful ECRH assisted breakdown is achieved at low loop_voltage ~ 3V. The ECRH power is launched around 45ms prior to loop voltage. The hydrogen pressure in tokamak is maintained ~ 1x10 -5 mbar and the pre-ionized density is ~ 4x10 12 /cc. At 1.5T operating toroidal magnetic field, the ECH power is launched in fundamental Omode. The ECH power at fundamental harmonic is varied from 100 kW to 250 kW and successful breakdown is achieved in all ECRH shots. In fundamental harmonic there is no delay in breakdown while at second harmonic ~ 40ms delay is observed, which is normal in case of second harmonic ECRH assisted breakdown.