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This paper presents a status data transmitting system suitable for vessel monitoring. The system consists of four main parts, which are a status data module, a frequency synthesizer, a power amplifier and a horn antenna. The status data module packs information of the identification, longitude, latitude and state of the vessel into data frames. FSK/MSK/GMSK schemes were used to modulate the data. The frequency synthesizer was designed with very high stability over temperature and very low frequency tolerance. The power amplifier provides 130 W output power at S band. The impedance bandwidth of the horn antenna can be controlled using the beveling technique.

In satellite technology, the communication between space segment and ground segment plays a vital role in the success of the mission. This paper is targeted at study, design and fabrication of a microwave active filter for the receiver front-ends using coupled line filter structure, which can be applied to the nanosatellite's communication subsystem. The whole active filter module is a combination of a microstrip bandpass filter and a preceding twostage wideband low noise amplifier using FET devices. The proposed module operates in the frequency range of 2 -2.4 GHz, which can be divided to 10 frequency slots of about 40 MHz for each. These frequency slots will be used for the S-band multi-frequency receiving function of the ground station, as well as the nanosatellite. The simulated and measured results of this active filter configuration are presented.

In satellite technology, the communication between space segment and ground segment plays a vital role in the success of the mission. This paper is targeted at study, design and fab rication of a microwave active filter for the receiver front-ends using coupled line filter structure, which can b e applied to the nanosatellite's communication sub system. The whole active filter module is a comb ination of a microstrip b andpass filter and a preceding two-stage wideb and low noise amplifier using FET devices. The proposed module operates in the frequency range of 2-2.4 GHz, which can b e divided to 10 frequency slots of ab out 40 MHz for each. These frequency slots will b e used for the S -b and multi-frequency receiving function of the ground station, as well as the nanosatellite. The simulated and measured results of this active filter configuration are presented.

The paper presents a wideband 3-dB quadrature coupler designed for operation at 2 GHz. The presented coupler is based on a broadside-coupled suspended structure in combination with a proposed defected ground structure (DGS) allowing for high power, wide-band and improved harmonic suppression performance. The experimental results show 0.2 dB of insertion loss, return loss of better than 18 dB and isolation of better than 25 dB in the frequency range from 1.74 to 2.67 GHz. The proposed coupler is able to be integrated in the status data transmitting system, which is suitable for vessel monitoring. The fundamental characteristics of the implemented coupler have been measured and verified.