Conferences

An Open Source Arduino based tracking System for Radio and Optical Telescopes

The current astronomical theory is that the Earth rotates on an axis through the north and south poles approximately once every 24 hours, this motion means that an observer on the surface must constantly move the angle of view to compensate. Small to medium size optical telescopes can achieve this by means of a mounting which has an axis aligned with the polar axis, so a constant speed motor drive is all that is required to track celestial objects. Larger optical telescopes, especially portable instruments, and radio telescopes are much easier to build with an “Alt/Azimuth” mount, like a gun carriage, however this means that complex mathematics or a video based guidance system are needed for long observations.

This paper introduces a cost effective solution to driving stepper motors with Arduino microcontrollers to change the altitude and azimuth bearings as required. Emphasis is on easy field use, simple construction and low cost. No complex calibration or mathematical knowledge is required to use it.

Benchmarking Electronic Calibration of USB-enabled Network Analyzers

These days, many instrument calibrations are performed automatically – for example, using electronic calibration units.  This includes calibration of vector network analyzers (VNAs) where the calibration standards are generated electronically rather than using mechanical devices.  However, verifying performance – particularly accuracy – of these electronic units is more difficult due to the “black box” nature of these devices. This paper describes a benchmarking exercise of a new-to-market electronic calibration unit designed specifically for use with a portable USB-driven VNA. This includes a comparison of performance with mechanical calibration kits and a comparison with the most accurate measurements available, obtained using primary national standards.

Design & Measurement of a 4Rx, 4Tx Ka-band Beamforming Transceiver in Bulk CMOS Silicon Technology for Satellite Terminal Applications

This paper presents the design and measurements for a K/Ka-band transceiver for phased array satellite mobile ground terminal applications. The transceiver integrates four receiver (Rx) RF paths operating at 17∼21GHz and the four transmitter (Tx) RF paths operating at 27∼30GHz, each with independent 0.5dB gain and 5-bit phase control to support analog RF and hybrid beamforming. Each Rx RF path is summed in an integrated passive combiner before an IQ frequency down conversion stage driven with a LO frequency doubler. Each Tx RF path is driven from an integrated IQ modulator clocked with an LO frequency tripler with an active power splitter. The Rx and Tx baseband (BB)/IF paths consist of 325MHz wide IQ VGAs and filtering to support up to 650MHz instantaneous bandwidth. Design for reliability using an automotive qualified bulk CMOS silicon process will be discussed and performance measurements demonstrated.  

Embedded Die Packaging for Phased Array

Many of the megatrends in technology we are currently seeing are driven by an increase in the number, and complexity of sensors and communication systems, this is true for civilian applications such as future telecoms, satellite communications and equally for airborne platforms. Across this space there is an underlying trend to make them smaller, more energy efficient, and improve the data rate using phased array systems to focus the energy where it is needed.   

High performing phased array systems are more challenging the higher up in frequency they operate due to smaller size, worse efficiency, extreme heat fluxes, and increased sensitivity to parasitic. To enable these systems, new packaging and integration solutions that enable efficient cooling while minimizing microwave parasitic and losses and maintaining reliability are needed. More efficient, highly integrated, and compact sensors and communication systems reduce weight, enable more efficient integration, and reduce energy consumption, which are all key drivers for future airplanes and airborne platforms. Furthermore, small, and light weight sensors at a lower cost would enable more widespread adoption of detect and avoid radars as well as imaging landing radars for all weather landings for commercial airplanes. This would result in safer flights, as well as reduced energy consumption.  

This paper, present developing a new compact, lightweight, energy efficient, reliable, and cost-efficient solution for microwave front-end modules. We will integrate multiple transceivers in a single module and embed common building blocks of a communication/sensor system such as amplifiers and filters. Focus was embedding GaN MMICs due to the high power and high temperature capability of this relatively new semiconductor technology. The antennas equally lend themselves to being integrated in the module or surface mounted, and this project will provide an interface to enable this. 

The improvements in the developed packaging technology would directly address commercial microwave sensor and communications systems. 

Meeting the Needs for Extended Pulse Capability in GaN Transistors and MMICs

As GaN has become the dominant semiconductor technology for RF power so the system architecture is evolving to take advantage of the capabilities of this new material.  For radar applications this has for example lead to extended pulse lengths that enables the increased range resolution needed to distinguish between 2 or more targets on the same bearing.  Long pulse lengths and increased duty cycle, however, place challenges on the device design.  The high power density that allows for smaller device size has a downside when trying to remove the dissipated heat from the same small area.   In this presentation we’ll look at some of the considerations needed in designing for long pulse operation and review the capability that can be achieved from state of the art devices.

RF Frontend for a Full Duplex Radar Platform

Full-duplex (FD) or simultaneous transmit and receive (STAR) allows the reception of one signal while simultaneously transmitting another on the same frequency and timeslot. Previously this technique has been proposed for wireless networks and mobile communications. This work considers applying FD technology to an X-band weather radar to allow the reception of an echo during the transmission pulse, thereby reducing the minimum target detection range. This paper looks specifically at the development of an RF frontend to verify the concept. The RF frontend up- and down-converts a 50 MHz intermediate frequency (IF) to 9.45 GHz in two-stages with an intermediate IF of 2.4 GHz. The design, simulation, and production of the 9.45 GHz RF Self-interference canceller (SiC) and the IF filters are presented. The RF SiC achieved 66.1 dB of narrowband cancellation at 9.45 GHz with a realistic horn antenna. When combined with the converters, 56.3 dB of cancellation was achieved at 50 MHz with a 2 MHz wide frequency modulated continuous wave (FMCW) pulse.

The Advantages of Star Mixers Compared to Quad Diode Rings for the Realisation of Double Balanced Microwave Mixers

Most commercially available, high linearity double balanced mixers adopt a quad diode ring topology. This is an excellent choice with many performance advantages. However, a star topology is functionally equivalent but offers a significant advantage in having inherently lower IF parasitics. This allows the realisation of mixers with much wider IF bandwidth, extending up into the RF and LO frequency bands. This paper describes the realisation of typical quad ring diode mixers and presents a practical example designed by PRFI. It then compares the achievable performance of a quad ring mixer to a star mixer, realised on the same process and targeting the same operating band.