Pushing past the tipping point: how Singapore is leading the charge in electric vehicles

by Kumail Rashid, EV Charging Solutions Lead, Asia Pacific, ABB

The technologies deployed highlight the economic, social and environmental gains possible.

Global take-up of electric vehicles (EVs) is on track to reach the tipping point of swift mass adoption, with BloombergNEF predicting that more than half of new cars sold in 2040 will be electric. The Asia Pacific Region, in particular, will be a fascinating landscape to watch, with the region expected to see the highest EV growth. As the global race to electrify transport heats up, Singapore is charging ahead with its recent announcement of a SGD 30 million investment for EVrelated initiatives. Bolstered by supportive regulations and a bold vision for EVs, the city-state offers an ideal microcosm of the future of EVs and what the path towards mainstream adoption will look like.

Consumer concerns still remain one of the most critical barriers to EV adoption. According to a 2021 Deloitte study, range anxiety (the fear that one’s EV will not have enough charge to reach the destination) was one of the top concerns for consumers in most countries. Fast-charging stations, which make a quick recharge enroute possible and convenient, will therefore be key to addressing such worries. To this end, Singapore is scaling up the deployment of fast-charging stations island-wide, setting an ambitious goal of 60,000 EV charging points by 2030. Some recent initiatives include SP Group’s partnership with ABB to build a target of 1,000 DC fast-charging stations across Singapore, or the delivery of 50 kW Terra 54 DC fast-chargers at 10 Shell stations, which will allow consumers to charge their vehicle’s battery from zero to 80% in around 30 minutes. EV charging solutions have developed rapidly in the past few years, going beyond mere battery charging to offer a seamless and truly integrated transport solution. Technology has enabled EV chargers to connect to back offices, payment platforms and smart grid systems. To further minimise downtime, some EV chargers also include remote charger status monitoring, diagnostics, repair and over-the-air software updates. This fast scaling up of infrastructure and technological developments will be key in offering consumers a much

needed peace of mind, accelerating the adoption of personal and commercial EVs in Singapore.

The EV revolution has been developing in tandem with another critical shift in the automotive and transport sector - autonomous vehicles. With self-driving cars Mr Kumail Rashid and robotaxis still in the nascent stages, we have a huge opportunity to accelerate our transition to zero-emission electric transport by electrifying autonomous vehicles right from the start. Leading the way in electric autonomous vehicles, Singapore recently launched the world’s first, 12 m, fully electric autonomous bus - a collaboration by the Nanyang Technological University, the Land Transport Authority, and Volvo Buses. Using ABB’s HVC 300P fastcharging system, the 40-seater bus can be recharged quickly in 3 minutes to 6 minutes, at the end of the line, without impacting the normal operation of the route. With industrial emissions being one of the key polluters in Singapore and across the world, Singapore’s new automated guided vehicles (AGVs) are another exciting development. Electric AGVs, powered by ABB’s smartcharging ports, will be deployed at Singapore’s new Tuas port facility which is expected to be the largest in the world by 2040, with an annual capacity of 65 million containers. A stellar example of the merging of autonomous technology and electric vehicle technology, this is a great stride towards the industrial application of electric AVs.

The ABB DC fast charging stations can recharge EV batteries in about 30 minutes, while offering convenience to users with an experience akin to a fuel station. Over 100 EV charging points were deployed across Singapore in 2020, creating the largest DC charging network in the country. Image by ABB.

by Dylan McGrath, Senior Industry Solutions Manager, Keysight Technologies

5G promises dramatic improvements over previous generations of wireless communications technology, particularly in speed, latency, bandwidth, and quality. Most of the gain comes from the utilisation of 5G Frequency Range 2 (FR2) found in the millimeter-wave (mmWave) spectrum.

Mr Dylan McGrath

The mmWave spectrum is relatively under-utilised, meaning there is plenty of available bandwidth, and mmWave transmissions are smaller than other wireless communications signals, which makes them ideal for high-speed transmissions in dense urban areas, where many devices operate in close proximity.

However, mmWave's advantages for 5G communications are partially offset by technical challenges. To begin with, mmWave does not propagate very far - the transmissions are easily absorbed by the atmosphere and do not penetrate trees, building walls, and other infrastructure. Accurately measuring the performance of mmWave devices with over-the-air (OTA) test equipment and methodologies is difficult. The wide bandwidth of mmWave also degrades the signal-to-noise ratio (SNR) because the energy from the signal spreads across the bandwidth. Finally, mmWave uses higher-order modulation schemes to improve spectral efficiency, which in turn requires improvements in error vector magnitude (EVM) performance.

Excessive path loss is among the most vexing and commonly cited challenges to 5G mmWave communications. Path loss between the device under test and the measurement equipment decreases the SNR, making it difficult to make accurate measurements for metrics, such as EVM, adjacent channel power, and spurious emissions.

Compounding the issue, the small size of components and antenna arrays eliminates the possibility of placing probes for conducted tests, necessitating the use of OTA - or radiated - test. The OTA testing requirement, combined with the excessive signal path loss of mmWave transmissions, requires control and calibration of the radiated environment around the test setup.

Offsetting signal path loss requires flexible signal analyser hardware and software that enable the creation of the optimum solution for a specific signal and measurement. For example, a signal analyser can apply attenuation at higher power levels or a preamplifier at lower power levels to measure a variety of input signals. Signal analysers provide several RF signal paths to lower noise, improve sensitivity, and reduce signal path loss.

By default, in the signal analyser's standard signal path, the input travels through the RF attenuator, preamplifier, and preselector before reaching the mixer. This signal path is ideal for measuring low-level signals that have a bandwidth of less than 45 MHz.

mmWave wideband signals can be particularly challenging to measure. Bypassing the signal analyser's preselector is a good option when increasing the RF analysis bandwidth to analyse wide-bandwidth vector signals, because it allows wide-bandwidth signals to pass unimpeded through the RF chain. Not only does bypassing the preselector enable wideband analysis, but it also removes the amplitude drift and the preselector's passband ripple, further improving the overall accuracy of the measurement.

The low-noise signal path is well suited for making EVM measurements and other measurements that test transmitter modulation quality at higher power levels. Since the gain of the amplifier, frequency responses, and insertion loss are compounded at higher frequencies, bypassing the lossy switches in the preamplifier path and the preamplifiers provides the optimal RF signal path. This path reduces path loss and the frequency responses and noise created by the preamplifiers and switches. Choosing this signal path for wideband EVM measurement results at higher frequencies increases measurement sensitivity and improves signal fidelity.

A full-bypass signal path reduces path loss, improves signal fidelity, and increases measurement sensitivity. A full-bypass signal path can reduce loss at mmWave frequencies by up to 10 dB compared with the default signal path.

The full-bypass signal path is a combination of the low-noise signal path and the microwave preselector bypass path, avoiding multiple switches in the low-band switch circuitry as well as the microwave preselector. While the advantages of using the full-bypass path are clear, this path has a few drawbacks, including potential in-band imaging and low SNR for testing low-power signals. However, eliminating images in the band of interest by adding a bandpass filter can improve EVM results by 1 to 2 dB. An external preamplifier can also enhance the SNR when testing lowpower signals.

Another critical element that impacts the accuracy of 5G mmWave measurements is the input mixer level. The input mixer-level setting of a signal analyser offers a tradeoff between distortion performance and noise sensitivity. As discussed above, SNR is decreased in 5G mmWave signals due to wideband noise and excess path loss, leading to poor EVM and adjacent power ratio measurements that do not represent the actual performance of the device under test (DUT).

The signal analyser’s input mixer is another tool that can help overcome the challenges of 5G mmWave frequency measurements. The optimum mixer-level setting is dependent on the measurement hardware, input signal characteristics, and specification test requirements. It is also possible to apply an external low-noise amplifier (LNA) to the signal analyser’s front end to optimise the mixer's input level. Some new signal analysers such as Keysight’s N9042B UXA X-Series signal analyser include a LNA in the signal path, along with the preamplifier. This allows users to achieve the benefits of using a LNA to optimise the mixer’s input level without requiring external components.

To get the best EVM measurement results, the intermediate frequency (IF) noise of the signal analyser must be low enough that it does not further decrease the SNR. The input signal to the digitiser must be high enough, yet not too high that it overloads the digitiser. The optimum balance is a delicate dance that requires a combination of RF attenuator, preamplifier, and IF gain value based on the signal peak level. New signal analysers enable users to optimise these hardware settings at the touch of a button, improving SNR while avoiding digitiser overload. However, manually tweaking settings such as IF gain and RF attenuators is often necessary for the optimum settings, yielding the best measurement results.

Components in the signal path Another critical factor to consider for making accurate 5G mmWave measurements is the impact of components in the path between the signal analyser and the DUT. The components in the signal path can degrade the signal analyser's overall measurement accuracy.

Measurement accuracy becomes even more critical as bandwidths grow wider and frequencies rise into the mmWave spectrum. With smaller margins for error, engineers need to find ways to eliminate frequency response errors, which occur at different frequencies and impact phase and amplitude responses. Signal analysers provide an internal calibration routine to correct their frequency responses.

Cables, connectors, switches, and fixtures in the signal path between the signal analyser and the DUT can degrade measurement accuracy because of frequency response errors. Using different amplitude correction configurations and complex corrections can help remove frequency responses, providing a more accurate picture of the DUT performance.

Signal analysers enable the configuration of both amplitude and complex corrections to correct frequency responses (although a high-performance signal generator or a vector network analyser is required to calibrate the test network). Using a signal generator in combination with a power meter and sensor to measure amplitude, then inputting the correction values into the signal analyser, is an effective method for making amplitude corrections. New receiver calibrators that are specifically designed for signal analyser receiver measurement systems, such as Keysight’s U9361 RCal receiver calibrators, provide a transfer standard enabling both absolute amplitude and complex magnitude and phase corrections.

The promise of 5G - especially the mmWave FR2 band of 5G - is clear. It provides a step function increase in speed, bandwidth, and performance and will ultimately enable entirely new use cases and business models. But working with mmWave frequencies presents obstacles, particularly in terms of path loss, that make it challenging to make accurate, repeatable measurements. Understanding and utilising the various RF signal path options on your signal analyser can help you overcome these challenges when making 5G mmWave measurements.