Conferences

A coherent, multichannel signal generator for a 5G mmWave antenna test-bed

The paper will describe the design (a bit) and implementation (a bit more) of a 2-channel generator based on up-conversion of a directly synthesized IF.   By taking a totally different approach we were able to deliver a system that met the basic requirements for the target system at significantly lower cost than using the obvious IQ Baseband – Vector Generator combination. Nothing come for free – so I will touch on some of the trade-offs of this approach, and some possible enhancements, should we do another similar system in future.

A GaAs SP8T Switch Design for E-Band Automotive Radar

A GaAs Single Pole Eight Throw (SP8T) switch design, simulation and measured performance in a frequency range of 76-81 GHz is discussed. The switch is intended to be used in the RF-frontend design of an E-band FMCW automotive Radar system. UMS foundry’s Schottky diode process is used for the design and fabrication as it exhibits very low junction capacitance and series resistance for the diode. On-wafer measured insertion loss and isolation of the designed SP8T is <6 dB and >24.9 dB respectively from 76-81 GHz. On-wafer measured input and output return losses are >10 and 12 dB respectively both in open condition and when one switching arm is closed. The paper discusses the design technique for a multi-throw switch at such high frequencies where phase imbalance in the switching arms poses limitations. Use of a SP8T switch would reduce a number of transition losses as compared to if either SPDT or SP4T were used, specifically at such high frequencies. Assembly related costs and losses are also reduced due to the reduced number of chips being used. Hence, overall system performance is improved which is critical at such frequency range and for the application.

Class BJF-1: Simplifying the design methodology of RF Power amplifiers

We present Class BJF-1, a new class of amplifier that achieves efficiencies higher than class B/J/J* for a large range of possible load impedances that considerably simplifies the design space. The formulation for this class encompasses Class J (High linearity), CCF-1 (high efficiency), extended CCF-1, and saturated PAs. We can choose better amongst this range to achieve the desired target performance. Three PA prototypes were designed by selecting impedances within the design space. All three fabricated amplifiers using a GaN HEMT CGH40010F achieved measured PAE in excess of 72%, and saturated output power Pout in excess of 41 dBm. The measured P1dB ranged from 30 dBm to 35 dBm, as chosen by design. Moreover, a 3dB bandwidth of 800 MHz was observed, despite using only narrowband techniques. This is because of the large design space coupled with a simple strategy of an impedance transformer in the matching network. The best performing amplifier achieved 79.7% drain efficiency and 42.2 dBm saturated output power at 2.6 GHz, giving a frequency weighted efficiency (FE= (average efficiency)*?Center Freq) of 92.4%?GHz, representing one of the highest figures of merit achieved with this device reported to date.

Design of a 5W GaN MMIC power amplifier for Ka-band application

The design of a 26-31GHZ 5W GaN on SiC MMIC for 5G and Satcomms application is presented. The design flow is based on characterisation of unit cells using a Focus Microwaves active load pull system to produce a Cardiff type behavioural model, together with a compact equation based model derived from pulsed IV and S-parameter measurements. A comparison of the behavioural vs compact model approach and their complementary use in a new PA design flow is described. Measured PA results show the effectiveness of the approach with 4W Psat obtained across 26-30GHz with PAE>25%.

Mechanical Design Techniques for maximizing PCB space and reducing system size and weight

Traditionally high frequency applications have used metal multi-cavity clamshell shields screwed down to the PCB.  To minimize the gaps, they would either place screws a few cm apart or place an extruded gasket on the walls and move the screws farther apart.  Both solutions require a wide PCB trace and excessive bosses that increase the weight of the metal and uses excessive amount of PCB space.  There are techniques that can reduce the amount of screws needed, while thinning the walls which will provide both weight reduction and width of the PCB traces (as low as 0.5mm). 

Another key item for reducing overall system size and weight is the removal of heat.  Metal is the only reasonable method for removing heat, but by using design techniques such as heat pipes or vapor chambers, you can increase the efficiency of the heat transfer which will allow you to reduce the overall fin and metal size.  You can quite often add the gaskets to the bottom of the thermal module to provide a single part for both heat and shielding with a single part.

Mm-wave/THz Multi-Gigabit Wireless Links

The demand for broadband content and services worldwide is growing at a tremendous pace. Soon, traffic from wireless devices will exceed that of wired setups. Currently, high-resolution videos account for about 69 % of all data viewed on mobile devices and are expected to reach 79 % by 2020. At this pace, short-range wireless communication will soon require data transfer speeds of tens of gigabits per second (Gbps), which current wireless technology cannot support. A host of technologies are being actively researched to meet this challenge. In this talk, we will describe our research on the resonant tunnelling diode (RTD) technology to create ultra-broadband wireless communications. RTDs are compact, high-speed semiconductor devices that can function as transmitters and receivers. They can be modulated using electronic or optical signals and can also be used to modulate lasers. This makes them potentially valuable as a link between fibre and wireless domains. We will report on short range wireless links with data rates of over 10 Gbps using new RTD transmitters developed for the 100 GHz and 300 GHz regions of the radio spectrum. These speeds are over 1 000 times faster than the rates available at the moment.

The Quantum World: From Laboratory to Industry

Recent advancements in quantum technology mean we can exploit the fundamental properties of atoms and particles and apply quantum mechanics to real world applications. Some of the applications Teledyne e2v are focussing on include quantum sensors for civil engineering and oil and gas, space based quantum sensors with applications in Earth observation and quantum clocks for navigation and timekeeping resilience. Quantum sensors offer advantages to existing technologies such as ground penetrating radar which are used to map under the ground. Similarly quantum clocks offer benefits to existing technology. This talk will give an overview of quantum technologies being commercialised at Teledyne e2v, an insight into how RF and microwave frequencies are used in the devices being developed and a comparison to existing technologies.