S-99 Antenna Systems Trainer comprises of two towers for mounting the transmitting and receiving antenna, synthesized receiver, synthesized rf source with tracking facility and accessories like 20 antennas, antenna stepper positioner, directional coupler, etc. All the antennas are matched for a typical VSWR<2 and have been designed by Prof Girish Kumar, Elect Engg Dept, IIT Bombay, India.

S- 99 Antenna Systems Trainer works in stand alone mode as well as in conjunction with a PC. Polar Plots of the Antenna can be printed directly on an epson printer. STS-3006 Antenna Analysis Software greatly enhances the understanding of electromagnetic concepts and measurement capability. The whole system can be easily accommodated on a standard laboratory bench. Distance between transmitting and receiving antennas is typically 3 to 6 meters for use within laboratories. However, due to the high sensitivity and wide dynamic range of the receiver the distance can be increased manifold.

The receiver measures the incoming signal picked up by the receiving antenna. The input impedance is 50 ohms and the frequency range is 50 to 1300MHz. Frequency can be entered manually via the key board or via software. Wide dynamic range (100dB), 0.1dB resolution, 3dB typical level accuracy, 125KHz frequency resolution and narrow resolution bandwidth (300KHz typical) allow accurate spurious free measurements. The receiver also has a built-in positioner controller (via centronics port) and a serial port (RS232) for computer interface. The receiver connects to the transmitter generator via a co-ax cable for making tracking measurements.

The transmitter is a 50 ohms synthesized rf source to drive the transmitting antenna. Frequency can be keyed-in manually via the keypad or controlled by the receiver. The typical output is 115dBuV with a frequency resolution of 125KHz.

The stepper positioner rotates the Antenna in 1deg or 5deg steps. The stepper is controlled by the receiver via centronics interface to make synchronous measurements.

The antennas have been divided in three categories: Classical (7 antennas), Printed (7 antennas) and Microstrip (6 antennas). All the antennas are properly matched and have a VSWR<2 at the frequency of operation.

Three Dipoles, Monopole, Planar Monopole, Square Loop, Quad, Slot, Helical, Three Yagi-Uda (3, 5 & 7 elements) Log-Periodic, Rectangular Patch (Lossy), Rectangular Patch (Suspended), Compact Microstrip, Circularly Polarised Patch, Broadside and Endfire Array and Spiral

The current probe (red) gives a voltage output proportional to the current flowing through an antenna element.

The voltage probe gives an output voltage proportional to the voltage induced by the antenna element.

The directional coupler is of robust design, for the measurement of Vincident and Vreflected, for the computaion of VSWR. The useable range is 0.1 to 1.3GHz with a typical midrange directivity of 20dB.

Polar & Cartesian Plots, 5 Polar Plots, Antenna Frequency Bandwidth, Beamwidth, Gain, Side Lobe, Angle, Spectrum, Forward / Reverse Voltage, VSWR vs Freq, RF Recorder, Polar / EMI - Cursor measurements etc are possible via RS232.

Optional available features are 3D Polar Plot and Vertical Plane Plot features. - Requires Pentium 3+ and Microsoft Windows 98 / 2000 / XP.

Lab & Operating Manuals
Book "Antennas Made Easy" by Prof Girish Kumar
                                               * December 2003 onwards