RF and Microwave Power Transistors

This paper reviews the history, evolution, and applications of silicon microwave & RF power transistors and electric power devices. The current status of silicon microwave & RF power transistors (BJT, DMOSFET, SIT) and a new kind of electric power device - RSD in HSRI are mainly presented. Important techniques for manufacturing such power devices are introduced. Future trends of such power devices are given briefly.

More and more devices, such as Bluetooth and IEEE 802.15.4 devices forming Wireless Personal Area Networks (WPANs) and IEEE 802.11 devices constituting Wireless Local Area Networks (WLANs), share the 2.4 GHz Industrial, Scientific and Medical (ISM) band in the realm of the Internet of Things (IoT) and Smart Cities. However, the coexistence of these devices could pose a real challenge—co-channel interference that would severely compromise network performances. Although the coexistence issues has been partially discussed elsewhere in some articles, there is no single review that fully summarises and compares recent research outcomes and challenges of IEEE 802.15.4 networks, Bluetooth and WLANs together. In this work, we revisit and provide a comprehensive review on the coexistence and interference mitigation for those three types of networks. We summarize the strengths and weaknesses of the current methodologies, analysis and simulation models in terms of numerous important metrics such as the packet reception ratio, latency, scalability and energy efficiency. We discover that although Bluetooth and IEEE 802.15.4 networks are both WPANs, they show quite different performances in the presence of WLANs. IEEE 802.15.4 networks are adversely impacted by WLANs, whereas WLANs are interfered by Bluetooth. When IEEE 802.15.4 networks and Bluetooth co-locate, they are unlikely to harm each other. Finally, we also discuss the future research trends and challenges especially Deep-Learning and Reinforcement-Learning-based approaches to detecting and mitigating the co-channel interference caused by WPANs and WLANs.

: This handbook summarizes nuclear weapon effects on communication and navigation systems and provides information for determining if sophisticated analyses are required for system evaluation. It replaces DASA 2090. Keywords include: Nuclear weapon effects, Communication systems, Navigation systems, ELF- HF Communications systems, Line-of-Sight communication systems, Troposcatter communication systems, Ionoscatter communications systems, and Meteor burst communication systems.

The 2.4 GHz industrial, scientific and medical (ISM) band is a shared electromagnetic resource where many wireless communications technologies such as wireless local area networks, Bluetooth, ZigBee, cordless phones, amongst others, coexist. Due to the large amount of users of different technologies that might utilize the band at the same time and geographical region, it is reasonable to assume that the band is very busy all the time. In this paper, however, a spectrum measurement campaign is carried out to determine the actual spectrum occupancy of the ISM band in an environment with high density of users. Although many wireless technologies share this frequency band, results show its low spectrum utilization. Indeed, it is shown that the spectral occupation of the band ranges between 7% and 34% of a normal working day, and it is moderate even during busy hours. Therefore, the use of a more sophisticated approach is essential to exploit the unlicensed access to this band, for which cognitive radio is well suited. This is valid despite the fact that, formally speaking, there are no licensed (or primary) users in the ISM band. Nevertheless, ISM users could be treated as pseudo-primary. Thus, cognitive radio techniques can be implemented to improve the spectrum utilization.

Traditional charge pumping (CP) technique relies on trap-assisted recombination from the source/drain to the body contact to characterize interface trap density (Nit) of classical bulk MOSFETs. A variant of the technique called single pulse CP (SPCP) allows interface trap characterization even if the bulk contact is absent, as in silicon-on-insulator (SOI) MOSFET. Unfortunately, neither technique is useful for devices with source-body-tied (SBT) and inhomogeneous channel doping profile, as in lateral diffused MOS (LDMOS) power transistors. Here, we propose a generalization of the CP/SPCP techniques, called Super SPCP (S2PCP), to extract position-resolved localized degradations (ΔNit) in an SBT LDMOS. Careful TCAD modeling and experimental characterizations demonstrate the effectiveness of the proposed approach. Our analysis provides deep insights into the physics of the SPCP technique, demonstrating that the approach can be used to characterize a variety of transistors with nontraditional doping profiles and contact configurations.

A compact coplanar waveguide (CPW) fed dual band antenna is designed within a compact size of 21.57 × 25.62 × 1.6 mm3. A prototype antenna consists of an outer closed ring resonator, inner split ring structure, inner most closed ring and modified ground plane. The radiating element is employed to cover −10 dB impedance bandwidth of 110 MHz (2.29–2.4 GHz) and 2210 MHz (3.35–5.56 GHz) with center frequencies of 2.36 GHz and 4.45 GHz, respectively. A CPW-fed line with modified ground plane yields good impedance matching and broad bandwidth of the antenna. The band characteristics of metamaterial-inspired split ring structure as well as negative permeability (μ) are explained in detail. The prototype antenna has consistent Omnidirectional (H-Plane), and dipole (E-Plane) radiation pattern are obtained both resonant frequency, which is significantly useful for Industrial Scientific and Medical (ISM) radio band, Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Local Area Network (WLAN) applications.

This paper comes with a new study on the conception of a CPW-Fed multi bands planar antenna. The design takes into account that this structure can be integrated with circuits behind, that why the Fed is a CPW one. The antenna validated is suitable for GSM, DCS and ISM band. The entire area of the antenna is 36×72.5 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and it is printed on an FR4 substrate. The printed U-shaped antenna is formed from two horizontal arms of different lengths and an L-shaped shorted strip which is connected between the vertical arm and the ground plane. The antenna is designed, optimized, and miniaturized by using ADS "Advanced Design System" and the results are compared with CST Microwave Studio.

Even invented and applied initially during the World War II, RFID (Radio Frequency IDentification) technologies [1] have attracted much attention recently. Precisely speaking, RFID technologies have been applied very widely in some proprietary or closed systems, for example, animal control [2], portal control (access badges), etc. in last decades. The main advantages of RFID application are, storing item data in an electronic way even for further update, data access by electromagnetic wave in a wireless manner, and allowing quick multiple accesses to RFID tags. Based on the diverse applications, different spectrum bands are allocated, for example, LF (125 134.2 kHz and 140 148.5 kHz) for animal control, HF (13.56MHz) for electronic ticket, and UHF (868 MHz-928 MHz) for logistics, etc. Most of the frequencies are located in the ISM (Industrial, Scientific and Medical) bands [1]. However, RFID was emphasized again mainly because of the need of supply chain [3]. By proposing a standard for the format of electronic data used for goods items, of which EPC (Electronic Product Code) [4] is an example, the products can be registered at once when they are shipped out from the factories in one country, and be released when they are checked out at the counter of a supermarket in the other country in the world. These products might have been transferred through Customs of many countries and carried by different traffic means. When being through these check points, the related data stored in the tags are updated. This is called “product tracking” and is to be carried out in an “Internet of Thing (IOT)” [5]. This Chapter is to have a review on the technology theme – how to provide low-cost RFID Tags, when RFID technology is to be applied into the logistics area where the RFID tags are supposed to be not re-usable and to be as “zero-cost” as possible. Generally speaking, there are three major parts composing a RFID Tag’s total cost, namely, antenna, chip and assembly for them. The cost of antenna, in addition to the design phase, is mainly dependent on the manufacturing process. Therefore, manufacturing process should be focused if antenna’s cost, then the tag, is concerned. This is the theme of this Chapter. Not like the other antenna applications, for example, wireless LAN or mobile phone, in which antennas need to be compliant to the end products’ appearance by following the market trend. In the tag antenna industry, on the contrary, it does not need to design or modify the tag antenna often. The tag antenna just needs to electrically match the chip used in the beginning of design. It is not necessary for tag providers to prepare a wide product spectrum in the market. Again, not like the mobile phone industry, RFID tag’s players just

In 1991, the European Telecommunications Standards Institute (ETSI) set up an ad-hoc group to study the possibilities for standardising radio LANs (RLANs). It was concluded that although medium and high bit rate systems (up to about 2 Mbit/s) could be created based on either the 1.9 GHz DECT (Digital European Cordless Telecommunications) standard or using the 2.4 GHz ISM (industrial, scientific and medical) band, there was a clear need for a new standard to provide very high data rates of around 20 Mbit/s. This new standard is called the High Performance Radio Local Area Network, or HIPERLAN, and companies from across Europe have successfully completed this standard. In February 1995, the standard was approved to go forward for public enquiry. Although this public enquiry process may lead to refinement of the standard, major changes are not envisaged, and the current status of the standard is presented. The initial phase of the work on HIPERLAN was to define the appropriate technical targets. These were set so as to be ambitious, but still considered feasible for implementation within a two to three year timescale. The key requirements for the design of the HIPERLAN standard are summarised in a table and are then described in more detail.

DeviceMaker—The In-House Developed TCAD Tool to Analyse and Estimate Semiconductor Device Internal Electrical Properties, and Measured DC Performance Characteristics of Commercially Available RF|Microwave and High Power Transistors

Wireless communication has experienced enormous growth during the past decade, primarily driven by mobile cellular systems for voice communications, but more recently by the use of wireless local area networks(WLANs) for corporate enterprises and hot spot areas. However, mobile operators will face many challenges both economically and technically, as WLAN evolve through a bewildering number of different standards during the coming years. Potentially this will require several upgrades to the WLAN infrastructure. A new approach for addressing these challenges is evaluated in this paper. It is based on a radio over fiber (RoF) technology that uses electro-absorption modulator (EAM) and off-the-shelf WLAN access point, and it promises to provide solutions that will be transparent to changes in protocols and frequency of operation as well as reducing radio access infrastructure costs

RF power amplifiers use a wide range of active devices, such as vacuum tubes and transistors (usually BJTs or MOSFETs). Vacuum tubes, still widely used in high-power RF amplifiers.

A compact 5GHz WLAN notched Bluetooth/UWB antenna has been proposed, fabricated, and characterized. The rectangular UWB monopole antenna has gained the Bluetooth frequency band and the notched frequency band by using a coupling-fed meander line and inverted L-shaped strips, respectively. The proposed antenna is a good candidate for integrated Bluetooth and UWB systems.

Fifth generation communication networks promise extremely high data throughputs, low latencies, and ultra-high reliability by employing small cells in high density networks. This will increase the use of highly inefficient microwave power amplifiers, that exhibit efficiencies sometimes as low as 10% for advanced multi-carrier waveforms. To overcome these inefficiencies and enable next generation technology development, the internal distributed behaviour of the packaged microwave power transistor has to be fully characterised, which is impossible using conventional port-based measurements. In this dissertation, the development of a set of multiphysics measurement techniques that capture the distributed electrical, electromagnetic, and thermal device behaviour is described. These new multiphysics measurement techniques enable the characterisation and direct visualisation of the inefficient device performance, providing a basis for future design optimisation. The techniques combine a non-linear vector network analyser, electro-optic, load-pull and thermoreflectance measurement systems that enable large signal time-domain electrical, distributed multi-harmonic vector electric field (E-field), and transient and steady-state thermal measurements. The multiphysics measurement set-up was used to characterise various transistors and PAs including 260 W silicon (Si) laterally diffused metal oxide semiconductor (LDMOS) field effect transistors in both air-cavity ceramic and plastic packages, 25 W gallium nitride (GaN) on silicon carbide high electron mobility transistors (HEMTs), 250 W GaN HEMT and 360 W Si LDMOS Doherty power amplifiers. The E-field measurements enabled the first ever imaging of parametric odd-mode oscillations within multi-die packaged high-power microwave transistors. Additionally, the measurement system was used to verify the effectiveness of in-package oscillation suppression circuits. As high-resolution E-field measurements can be slow, a surrogate modelling-based measurement algorithm was implemented to accelerate measurements 10-fold. Transient thermal measurements helped to identify abnormal transistor finger-to-finger heating in GaN HEMTs and revealed thermal differences along the gate width in GaN-based asymmetric transistors for Doherty power amplifier applications.

New generation of mobile communication systems will focus on seamlessly integrating existing wireless technologies including 3G cellular systems, wireless LAN and Bluetooth to create a wide coverage, improved capacity and enhanced QoS heterogeneous wireless communication system. It is envisaged that the next generation of wireless communication systems will support comprehensive and personalized services, providing stable system performance and quality of service. In this paper we investigate and analyse the performance of a wireless communication system which consists of an integrated cellular communication system and a wireless LAN radio access networks inorder to determine an optimum combination of radio access technologies in a coverage area for efficient handling of mixed traffic requests from mobile users.