This paper describes the design, simulation and practical results of a phase modulator based in an hybrid coupler and two varactor diodes in the band from 2.0 GHz to 3.0 GHz for TTC proposes. A minimum modulation index of 1.22 was obtained at the highest frequency to 1.57 at the lowest. This modulator consist of a two stages hybrid coupler with varactor diodes. Simulation is performed using ADS 2016.01. Even both varactor diodes are feed by the same modulation signal, each of them has his own voltage input for correct varactor impairments. In the measures, excellent isolation is achieved for the 1 st and 4 th port of the ring.

This paper presents a wideband voltagecontrolled oscillator (VCO) using hybrid technology based on bipolar transistors for a new generation TTC Transponder. The VCO is based on microstrip three-pole combline bandpass filter with just one varactor diode. The bandpass filter is embedded into the feed-back loop to treat as a frequency stabilization element. The VCO delivered 4.63 dBm maximum output power at 3.4 GHz with a current consumption of 17.4 mA for a supply voltage of 3 V and it has a tuning range achieved from 600 MHz being the frequency range from 2.8 GHz to 3.4 GHz. The developed VCO with three pole combline filter is experimentally demonstrated at 3.4 GHz with a phase noise of -126 dBc/Hz at 1 MHz offset frequency. In addition, over this frequency range, all the phase noises measured at 1 MHz are better than -118 dBc/Hz.

This paper presents a wideband voltagecontrolled oscillator (VCO) using hybrid technology based on bipolar transistors for a new generation TTC Transponder. The VCO is based on microstrip three-pole combline bandpass filter with just one varactor diode. The bandpass filter is embedded into the feed-back loop to treat as a frequency stabilization element. The VCO delivered 4.63 dBm maximum output power at 3.4 GHz with a current consumption of 17.4 mA for a supply voltage of 3 V and it has a tuning range achieved from 600 MHz being the frequency range from 2.8 GHz to 3.4 GHz. The developed VCO with three pole combline filter is experimentally demonstrated at 3.4 GHz with a phase noise of -126 dBc/Hz at 1 MHz offset frequency. In addition, over this frequency range, all the phase noises measured at 1 MHz are better than -118 dBc/Hz.