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High Frequency Radio Astronomy Laboratory

Views of the laboratory and some spectrometer components

	Laboratory testing of WASP2 and APHID spectrometer systems.
	The WASP2 circuit boards are four-layer hybrids of microwave and normal FR-4 circuit board material.  Most of the parts are surface-mount technology, allowing the boards to be assembled by pick-and-place robots.
	Suss PM5 probe station, oscilloscope, spectrum analyzer, synthesizer, 40 GHz network analyzer, and other equipment set up for testing a microwave integrated circuit
	Closeup of the probe station chuck with microwave and bias probes mounted on Quater micropositioners.
	This integrated microwave module, shown with the cover open, is a dual 4-8 GHz downconverter with a biphase modulator before the top mixer and an LO power splitter and monitor point.  The box to the left is a commercial 8 GHz oscillator.
	Our West-Bond 7400B wirebonding machine welds 0.001" diameter aluminum and gold wires to integrated circuit chips.
	A microwave integrated circut, with size about 1 by 1 mm, with bond wires connecting it to a circuit board.
	An Intel 80C251SB microcontroller handles all real-time tasks for the WASP2 spectrometer.  The ADC clock signals are also generated on this board with a programmable logic chip.
	A WASP2 spectrometer (bottom, 4U chassis) and power supply (top, 3U chassis).
	A dual-channel amplifier module for the WASP2 spectrometers.  From left to right, each strip contains a gain equalizer network, step attenuator, 4 GHz low-pass filter, amplifier, RF switch, and amplifier.  The small circuit board in the center contains the control electronics and a serial interface to the system computer.
	A computer-controlled automatic gain control board for the COBRA digital correlator in the CASIMIR instrument for SOFIA.  The 500 to 1000 MHz microwave section has two amplifier stages, step and voltage-variable attenuators, switches for bypassing some of the attenuators, a gain equalizer network, and power detectors at the input and output.  A high-resolution image shows the board with the shielding cover over the microwave section.
	The APHID correlator module and its control computer and electronics.  This correlator uses a single WASP2 circuit board for a 16-lag correlator with nearly 4 GHz bandwidth.  When combined with a 22 GHz receiver, the correlator measures the emission from a water vapor spectral line to find the amount of water over the antenna.  This information can be used to "detwinkle" the radio image measured by a millimeter wave interferometer.

Facilities and test equipment

• Two laboratory rooms with a total area of 700 square feet
• Agilent 8722D, 0.01-40 GHz network analyzer
• Suss PM5 microwave probe station with Spot Insight digital camera and GGB 40A microwave probes
• Synthesized sweep and CW sources to 20 GHz, with doublers for tests to 30 GHz
• HP 8648A, 0.1-3200 MHz synthesizer
• Agilent 8648D, 0.009-4000 MHz synthesizer
• HP 8671B, 2-18 GHz synthesizer
• HP 83752A, 0.01-20 GHz swept synthesizer
• HP 8559A 0.01-21 GHz spectrum analyzer
• HP 437B RF power meter with Agilent 8481D 18 GHz high-sensitivity sensor head
• SRS 770 FFT 100 kHz spectrum and network analyzer
• Agilent 1681A logic analyzer
• West-Bond 7400B wire wedge bonder
  
• Microscopes and a filtered-air clean bench for for fine work
• Pace PRC-2000 soldering station for multi-layer board and SMT device work
• Pentium computers with a large-format plotter and variety of CAD/CAM packages including AutoCAD,Protel DXP, and MMICAD
• Altera and Mentor Graphics PLD and FPGA programming and simulation tools
• Keil and Tasking compilers for Intel 80C251 and Phillips XA microcontrollers. We use the Phytec single-board minature computer series in our designs.
• Liquid nitrogen and helium test cryostats
• Alcatel ASM 120h helium leak detector
• Basic laboratory equipment such as power supplies, analog and digital oscilloscopes, voltmeters, lock-in amplifiers, tools, and parts stocks.

Notes and other information

• Nice notes on soldering from Weller (pdf).
• Notes and other practical information for the wire wedge bonder (pdf).
• Collected materials thermal data (txt).