This master thesis was part of a project at the Acreo Swedish ICT AB to investigate the 28 nm FDSOI CMOS process technology for the LTE front-end application. The project has resulted in a chip that contains different test circuits such as power amplifier (PA), mixer, low noise amplifier (LNA), RF power switch, and a receiver front-end. This thesis presents the evaluation of the RF power switch. At first, a stand-alone six-stacked single pole single throw (SPST) RF power switch was designed according to Rascher, and then it was modified to single pole double throw (SPDT) RF power switch according to the requirements of the project. This report presents an overview of the FDSOI CMOS process, basic theory of the RF switch, and the evaluation techniques. The post-simulation results showed that with the proper substrate biasing and matching (50 Ω), the RF switch will provide 2.5 dB insertion loss (IL) up to 27 dBm input power and over 30 dB isolation with 30 dBm input power at 2 GHz. / Detta examensarbete har varit en del av ett projekt på Acreo Swedish ICT AB för att undersöka 28 nm FDSOI CMOS teknik för LTE front-end tillämpningar. Projektet har resulterat i ett chip som innehåller olika testkretsar: effektförstärkare, mixer, RF-effektomkoppare, LNA, och en mottagarfront-end. Denna avhandling presenterar en utvärdering av RF-omkopplaren. En SPST RF-omkopplare med sex staplade transistor konstruerades enligt Rascher. Sedan modifierades konstruktionen till en SPDT-omkoppare i enlighet med kraven för projektet. Denna rapport presenterar en översikt över FDSOI CMOS-tekniken, grundläggande teori för en RF switch samt utvärderingsmetoder. Simuleringsresultaten visade att med rätt substratbiasering och matchning (50 Ω), så ger RF-omkopplaren 2,5 dB förlust (IL) på upp till 27 dBm ineffekt och över 30 dB isolering med 30 dBm ineffekt vid 2 GHz.

This report intends to impart a good understanding of routing modules used in modern transceiver systems. The radar system at RadarBolaget AB needed to have a good routing module for its newly designed transceiver antenna. In this report, studies have been done related to two majorly used routing modules in modern electronics industry; Microwave Circulator and RF/Microwave Switch. First off, different characteristics of routing modules are discussed. After having discussed important design parameters, practical design considerations for two routing modules are presented in a profound way. Theoretical knowledge for both of these two devices is presented in the beginning, followed by their practical designs using standard simulation software like HFSS and ADS. The report concludes its findings in a way that at the end of this report, reader becomes acquainted with ample information to be able to choose the best option available among all of the discussed designs. An FET RF Switch is chosen at the end of this project to be used for transceiver system which should be able to satisfy specifications specified by RadarBolaget AB. This project was carried out by two students of Master Program in Electronics/Telecommunications at Högskolan i Gävle in collaboration with RadarBolaget AB, Gävle, Sweden.

Yes / A printed dipole antenna integrated with a duplex RF switch used for mobile base station antenna beam steering is presented. A coplanar waveguide to coplanar strip transition was adopted to feed the printed dipole. A novel RF switch circuit, used to control the RF signal fed to the dipole antenna and placed directly before the dipole, was proposed. Simulated and measured data for the CWP-to-CPS balun as well as the measured performance of the RF switch are shown. It has demonstrated the switch capability to control the beam in the design of beam steering antenna array for mobile base station applications.

Chalcogenide phase change (PC) materials can be reversibly transformed between the high resistivity (~ 1 Ω∙m) amorphous state (OFF-state) and low resistivity (~ 10-6 Ω∙m) crystalline state (ON-state) thermally, both are stable at the room temperature. This makes them well suited as reconfigurable RF switches and non-volatile memories. This work will present the understandings of two key characteristics of PC materials, the crystallization dynamics and the threshold voltage (Vth), as they determine performance limitations in these applications. Crystallization dynamics describe the correlations of the states, temperature and time; the Vth is the trigger of the threshold switching which leads to the “break down” of PC materials from OFF-state to ON-state. The four-terminal indirectly-heated RF switches with high cut-off frequency (> 5 THz) has advantages over other technologies but its programming power (~ 1.5 W) is yet to be reduced. Measuring the maximum allowed RESET quench time in the crystallization dynamics is critical for designing low power switches. As a major contribution, this work provides a universal methodology for accurate heater thermometry and in-situ crystallization measurements for this study. On the other hand, understanding the Vth is essential for high power handling applications as it determines the maximum power that an OFF-state switch can withstand without being spontaneously turned on. This work will discuss new observations and learnings from Vth measurements including the geometry dependent Vth variations which provide insights into the threshold switching mechanism. Unlike RF switches, faster crystallization is desired for memories to improve the write speed. The non-Arrhenius crystallization needs to be explored to achieve short crystallization time (< 10 ns) at high temperature (> 700 K). As another major contribution, this work will present a nano-scale (~ 100 nm) high-speed (thermal time constant < 5 ns) PC device for assessing the crystallization time in this regime, and provide a comprehensive learning for the crystallization dynamics from 300 K to 1000 K by developing a unified framework based on the fragility model and growth-dominated crystallization. This can be used to accurately simulate the crystallization process for any device geometry and estimate the RF switches power and Vth.

In a wireless system, the frequency-reconfigurable RF components are highly desired because one such component can replace multiple RF components to reduce the size, cost, and weight. Typically, the reconfigurable RF components are realized using capacitive varactors, PIN diodes, or MEMS switches. Most of these RF switches are expensive, rigid, and need tedious soldering steps, which are not suitable for futuristic flexible and wearable applications. Therefore, there is a need to have a solution for low cost, flexible, and easy to integrate RF switches. All the above-mentioned issues can be alleviated if these switches can be simply printed at the place of interest. In this work, we have demonstrated vanadium dioxide (VO2) based RF switches that have been realized through additive manufacturing technologies (inkjet printing and screen printing), which dramatically brings the cost down to a few cents. Also, no soldering or additional attachment step is required as the switch can be simply printed on the RF component. The printed VO2 switches are configured in two types (shunt configuration and series configuration) where both types have been characterized with two activation mechanisms (thermal activation and electrical activation) up to 40 GHz. The measured insertion loss of 1-3 dB, isolation of 20-30 dB, and switching speed of 400 ns are comparable to other non-printed and expensive RF switches. As an application for the printed VO2 switches, a fully printed frequency reconfigurable filter has also been designed in this work. An open-ended dual-mode resonator with meandered loadings has been co-designed with the VO2 switches, resulting in a compact filter with decent insertion loss of 2.6 dB at both switchable frequency bands (4 GHz and 3.75 GHz). Moreover, the filter is flexible and highly immune to the bending effect, which is essential for wearable applications. Finally, a multi-parameter (switch thickness, width, length, temperature) model has been established using a customized artificial neural network (ANN) to achieve a faster simulation speed. The optimized model’s average error and correlation coefficient are only 0.0003 and 0.9905, respectively, which both indicate the model’s high accuracy.

Traditional antennas have a lot of limitations as their performance is usually fixed by their initial geometry. On the other hand, modern communication systems are getting way to complicated compared to their earlier counterparts. This necessitates some special types of smart or reconfigurable antennas, which can dynamically adapt to the requirements of the communication systems more effectively. Using conventional single functional antennas is therefore not an efficient approach in these sort of communication systems. Considering all these factors, in this thesis, a beam steerable reconfigurable antenna system is presented that can yield the radiation patterns of multiple antennas with a single structure, necessary for 5G communication. This antenna system occupies comparatively much smaller space and can provide highly directive gain at different directions. It is expected that- in near future, further improvements of this type of antenna system can be performed to pave the way for some additional necessary functions required in modern communication systems.

Radio-frequency (RF) switches are widely used in electrical systems, telecommunications, and wireless applications. In RF systems, it is often desirable to change the signal path effectively, by us-ing couplers, duplexers, and RF switches for signal division and combining. Typically, in modern RF systems, the RF switch is mostly capitalized in order to reduce the RF footprint but with efficient switch characteristics. A simple method to reduce transceiver space requirement is to integrate RF switches with the frontend module on a single chip. Recent advances in Gallium Nitride (GaN) technology allows RF designers to design faster, smaller, and efficient components using this technology. With high data rates in demand for wireless communication systems, wideband characteristics are needed in modern systems [1]. Therefore, it is desirable to design wideband circuits; such as, mixers, amplifiers, and switches. In this work, a comprehensive study of NRC GaN150 HEMT is conducted to design broadband RF switches. Single pole and double pole switch topologies operating at 1-12 GHz are designed to evaluate GaN 0.15μm RF switches. The main objectives were to design compact sized switches, while having high power handling, low insertion loss, high isolation and high return loss. Additionally, a transmit-receive switch is designed for integration into a frontend module and further fabricated to operate at 10 GHz. There are many applications of RF switches in an RF transceiver, one of which is an impedance tuner. Impedance tuner are attractive for many applications where mobile devices are used for wireless communications. As mobile technology continues to evolve, they are designed to be com-pact, leaving minimal space for the antenna. Consequently, the radiating element is often electrically small and sensitive to near-field coupling requiring tuning. Matching networks aim to tune matching conditions; for example, loading effects due to human hand [2]. For such situations, specialized matching networks can be designed to account for specific loading environmental effects. However, for mobile systems, the environment is unknown; thereby, yielding unpredictable antenna loading, especially for electrically small antennas that have rapidly changing real and imaginary impedance. As a result, it is necessary to design a reconfigurable impedance-matching network to account for possible load impedances. In this work, a 16-bit reconfigurable impedance tuner design comprising of passive microwave components and NRC GaN 0.15μm FET operating at X-band is presented to evaluate its performance for integration with the frontend module on a single chip to reduce cost and increase efficiency of the system.

RF switches are an essential building block in numerous applications, including tactical radar systems, satellite communications, global positioning systems (GPS), automotive radars, wireless communications, radio astronomy, radar transceivers, and various instrumentation systems. For many of these applications the circuits have to operate reliably under extreme operating conditions, including conditions outside the domain of commercial military specifications. The objective of this thesis is to present the design procedure, simulation, and measurement results for Radio Frequency (RF) switches in 130 nm Silicon Germanium (SiGe) BiCMOS process technology. The novelty of this work lies in the proposed new topology of an ultrahigh-isolation single-pole, single-throw (SPST) and a single pole, four-throw (SP4T) nMOS based switch for multiband microwave radar systems. The analysis of cryogenic temperature effects on these circuits and devices are discussed in this work. The results shows that several key-figures-of-merits of a switch, like insertion loss, isolation, and power handling capability (P1dB) improve at cryogenic temperatures. These results are important for several applications, including space-based extreme environment application where FET based circuits would need to operate reliably across a wide-range of temperature.

RF/Microwave switches are widely used in microwave measurement systems, telecommunication and radar applications. The main purposes of RF switches are Tx-Rx switching, band select and switching the signal between different paths. Thus, they are key circuits especially in T/R modules. Wideband operation is an important criterion in EW applications. High power handling is also a key feature especially for radars detecting long range. In this study, different types of high power solid state switches operating at X-Band are designed, fabricated and measured. The main objectives are small size and high power handling while keeping good return loss and low insertion loss. The related studies are investigated and analyzed. Solutions for increasing the power handling are investigated, related calculations are done. Better bias conditions are also analyzed. The measurement results are compared with simulations and analysis. Circuit designs and simulations are performed using AWR&reg / and CST&reg / .

abstract: Programmable metallization cell (PMC) technology employs the mechanisms of metal ion transport in solid electrolytes (SE) and electrochemical redox reactions in order to form metallic electrodeposits. When a positive bias is applied to an anode opposite to a cathode, atoms at the anode are oxidized to ions and dissolve into the SE. Under the influence of the electric field, the ions move to the cathode and become reduced to form the electrodeposits. These electrodeposits are filamentary in nature and persistent, and since they are metallic can alter the physical characteristics of the material on which they are formed. PMCs can be used as next generation memories, radio frequency (RF) switches and physical unclonable functions (PUFs). The morphology of the filaments is impacted by the biasing conditions. Under a relatively high applied electric field, they form as dendritic elements with a low fractal dimension (FD), whereas a low electric field leads to high FD features. Ion depletion effects in the SE due to low ion diffusivity/mobility also influences the morphology by limiting the ion supply into the growing electrodeposit. Ion transport in SE is due to hopping transitions driven by drift and diffusion force. A physical model of ion hopping with Brownian motion has been proposed, in which the ion transitions are random when time window is larger than characteristic time. The random growth process of filaments in PMC adds entropy to the electrodeposition, which leads to random features in the dendritic patterns. Such patterns has extremely high information capacity due to the fractal nature of the electrodeposits. In this project, lateral-growth PMCs were fabricated, whose LRS resistance is less than 10Ω, which can be used as RF switches. Also, an array of radial-growth PMCs was fabricated, on which multiple dendrites, all with different shapes, could be grown simultaneously. Those patterns can be used as secure keys in PUFs and authentication can be performed by optical scanning. A kinetic Monte Carlo (KMC) model is developed to simulate the ion transportation in SE under electric field. The simulation results matched experimental data well that validated the ion hopping model. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2015