Showing papers in "IEEE Microwave Magazine in 2020"
TL;DR: In this paper, the authors give an overview of parametric amplifiers, how they work, and where there are opportunities for improvement in parametric amplification for superconducting quantum computing.
Abstract: In superconducting quantum computing, qubit state information is conveyed via low-power microwave fields. As such, ultralow-noise microwave amplification plays a central role in measuring these fields to quickly and accurately infer the qubit state. To this end, parametric amplification, once a well-known concept for low-noise amplifiers during the 1960s and 1970s, has become the leading technology for enabling highly efficient microwave measurements of these quantum circuits. While current research efforts have elements in common with much earlier work, there are some important differences that distinguish this new generation of amplifiers. Here, we try to give an overview of what this excitement is about, how these devices work, and where there are opportunities for improvement.
88 citations
TL;DR: In this paper, the authors proposed a class of non-reciprocal structures endowed with extra functionalities, e.g., frequency generation, wave amplification, and full-duplex communication.
Abstract: The ever-increasing demand for high-datarate wireless systems has led to a crowded electromagnetic (EM) spectrum. This demand has successively spurred the development of versatile microwave and millimeter-wave integrated components possessing high selectivity, multifunctionalities, and enhanced efficiency. These components require a class of nonreciprocal structures endowed with extra functionalities, e.g., frequency generation, wave amplification, and full-duplex communication. Space-time (ST) modulation has been shown to be a perfect candidate for high-data-rate transmission given its extraordinary capability for EM-wave engineering. ST-modulated (STM) media are dynamic, directional EM structures whose constitutive parameters vary in both space and time.
78 citations
TL;DR: In this paper, the authors identify the new class of processes through which objects are built by selectively adding material, usually layer by layer, instead of subtracting material, as in conventional machining techniques like chemical etching, laser-cutting, milling, and electroerosion.
Abstract: Three-dimensional (3D) printing, additive manufacturing (AM), digital manufacturing, and free-form fabrication are some of the synonymous expressions commonly used to identify the new class of processes through which objects are built by selectively adding material, usually layer by layer, instead of subtracting material, as in conventional machining techniques like chemical etching, laser-cutting, milling, and electroerosion [1].
49 citations
TL;DR: This article focuses on the development of packaging for solid-state qubits and the use of 3D integration to address this challenge.
Abstract: Quantum processing has the potential to transform the computing landscape by enabling efficient solutions to problems that are intractable using classical processors. The field was sparked by a suggestion from physicist Richard Feynman in 1981 that a controllable quantum system can be used to simulate other quantum systems, such as the energy band structure of complex materials or the chemical reaction rates of intricate molecules. In the 1990s, interest in quantum computing grew rapidly with the introduction of the first quantum "killer app"-the potential of a large-scale quantum processor to break certain types of public encryption schemes [1]. Recently, there has been growing consensus that myriad other fields besides data security could be impacted by the development of a quantum processor, including machine learning [2], many optimization problems [3], and Feynman's original idea of the simulation of materials properties [4]. In recent years, the field has progressed rapidly, but many technical challenges must be overcome before a large-scale quantum processor can be built. This article focuses on the development of packaging for solid-state qubits and the use of 3D integration to address this challenge.
40 citations
TL;DR: These new application scenarios impose stringent requirements on wireless transceiver front ends and call for special considerations at the circuit and system design levels, including power amplifiers (PAs) to accommodate complex modulated signals.
Abstract: The next generation wireless network, 5G, is expected to provide ubiquitous connections to billions of devices as well as to unlock many new services through multigigabit-per-second data transmission. To meet the ever-increasing demands for higher data rates and larger capacities, new modulation schemes have been developed, and wider frequency bands, such as those at millimeter wave (mm-wave), have been designated for 5G [1], [2]. Massive multiple input/multiple output (MIMO), which uses a large number of antennas at the transmitter and receiver, has been considered one of the key 5G technologies to improve data throughput and spectrum efficiency [3]. These new application scenarios impose stringent requirements on wireless transceiver front ends and call for special considerations at the circuit and system design levels. In the transmitter, power amplifiers (PAs) should accommodate complex modulated signals, featuring a high peak-to-average-power ratio (PAPR) and a wide modulation bandwidth. Moreover, in massive MIMO arrays, PAs should maintain a high average efficiency to mitigate thermal heating issues.
38 citations
TL;DR: In this paper, the authors used microwave near-field imaging to evaluate hidden or embedded objects in a structure or media using electromagnetic (EM) waves in the microwave range, 300 MHz-300 GHz.
Abstract: Microwave imaging employs detection techniques to evaluate hidden or embedded objects in a structure or media using electromagnetic (EM) waves in the microwave range, 300 MHz-300 GHz. Microwave imaging is often associated with radar detection such as target location and tracking, weather-pattern recognition, and underground surveillance, which are far-field applications. In recent years, due to microwaves' ability to penetrate optically opaque media, shortrange applications, including medical imaging, nondestructive testing (NDT) and quality evaluation, through-the-wall imaging, and security screening, have been developed. Microwave near-field imaging most often occurs when detecting the profile of an object within the short range (when the distance from the sensor to the object is less than one wavelength to several wavelengths) and depends on the electrical size of the antenna(s) and target.
38 citations
TL;DR: The aim of this article is to introduce microwave engineers to quantum computing and demonstrate how the microwave community's expertise could contribute to that field.
Abstract: During the past decade, quantum computing has grown from a field known mostly for generating scientific papers to one that is poised to reshape computing as we know it [1]. Major industrial research efforts in quantum computing are currently underway at many companies, including IBM [2], Microsoft [3], Google [4], [5], Alibaba [6], and Intel [7], to name a few. The European Union [8], Australia [9], China [10], Japan [11], Canada [12], Russia [13], and the United States [14] are each funding large national research initiatives focused on the quantum information sciences. And, recently, tens of start-up companies have emerged with goals ranging from the development of software for use on quantum computers [15] to the implementation of full-fledged quantum computers (e.g., Rigetti [16], ION-Q [17], Psi-Quantum [18], and so on). However, despite this rapid growth, because quantum computing as a field brings together many different disciplines, there is currently a shortage of engineers who understand both the engineering aspects (e.g., microwave design) and the quantum aspects required to build a quantum computer [19]. The aim of this article is to introduce microwave engineers to quantum computing and demonstrate how the microwave community's expertise could contribute to that field.
34 citations
TL;DR: Massive MIMO is a critical technology that helps significantly in increasing network capacity and spectral efficiency, while reducing wireless network interference, ultimately improving the end-user experience.
Abstract: To accommodate growing user demand for faster data rates and extensive connectivity, modern wireless communication systems must evolve to support a sharply increasing number of subscribers, all requesting service at the same time. This trend encourages the broad application of multiple input/multiple output (MIMO) systems. In fact, MIMO techniques can increase data rates, coverage of service areas, and communication reliability without additional RFs. In recent proposals for 5G systems, the required separate RF chains in massive MIMO RF front ends can reach up to 256, with bandwidths of up to 800 MHz per RF chain [1], [2]. Massive MIMO is a critical technology that helps significantly in increasing network capacity and spectral efficiency, while reducing wireless network interference, ultimately improving the end-user experience.
31 citations
TL;DR: There are many steps in the design of a microwave filter: mathematically describing the filter characteristics, representing the circuit as a network of lumped elements or as a coupling matrix, implementing the distributed elements, finding the initial dimensions of the physical structure, and carrying out numerical tuning using electromagnetic (EM) simulators.
Abstract: There are many steps in the design of a microwave filter: mathematically describing the filter characteristics, representing the circuit as a network of lumped elements or as a coupling matrix, implementing the distributed elements, finding the initial dimensions of the physical structure, and carrying out numerical tuning using electromagnetic (EM) simulators. The whole process is painstaking and time-consuming, and it requires a great deal of engineering expertise. Microwave filters are extremely complex geometric structures, and their simple circuits are often quite hard to represent. Moreover, manufacturing them is costly: to be sure that the hardware resulting from the design will meet the performance goals, rigorous computer tools are used to determine the physical dimensions and evaluate all of the adjustments at the final stage. This last stage is particularly challenging, and advanced computational techniques are required.
25 citations
TL;DR: In this article, the current state of the art for terahertz (THz) packaging is reviewed and several novel techniques are described, including micromachined packaging.
Abstract: It is difficult to package and interconnect components and devices at millimeter-waves (mm-waves) due to excessive losses experiences at these frequencies using traditional techniques. The problem is multiplied manifold at terahertz (THz) frequencies. In this article, we review the current state of THz packaging and describe several novel techniques. As we will show, micromachined packaging is emerging as one of the best choices for developing advanced THz systems.
25 citations
TL;DR: This space covers a variety of different interconnect length scales and is most significantly experienced in terms of the interconnect technologies in large data centers (DCs) and high-performance computing (HPC) applications.
Abstract: The continued increase in computing capability that has occurred through the technology scaling foretold by Moore [1] and Dennard et al. [2] has led to a commensurate increase in the input-output requirements of computing systems. This phenomenon has been most significantly experienced in terms of the interconnect technologies in large data centers (DCs) and high-performance computing (HPC) applications. Historical data have shown a two to three times increase in aggregate data rates every two years [3]. This space covers a variety of different interconnect length scales. In a comprehensive survey by Thraskias et al. [4], high-speed interconnects are grouped according to the following taxonomy.
TL;DR: RF/microwave bandpass filters achieve their filtering functionality by means of the frequency-selective power reflection processing of the RF input signal, hence decreasing the mixer conversion gain.
Abstract: RF/microwave bandpass filters (BPFs) are fundamental components in high-frequency RF transceivers. On the transmitter side, they limit the transmitted RF signal bandwidth by suppressing out-of-band spurious signals and intermodulation products, which are primarily generated by the nonlinear active stages and can affect other RF systems. On the other hand, in the receiver, they reject out-of-band interfering/jamming signals and noise. Whereas a large variety of microwave BPFs have been proposed in the technical literature for multiple technologies (e.g., [1] and [2]), most of these BPF devices achieve their filtering functionality by means of the frequency-selective power reflection processing of the RF input signal. This means that those RF signals allocated within the operational bandwidth of the BPF are transmitted to the output terminal (with some tolerable added in-band loss and reflective-type filter, hence decreasing the mixer conversion gain.
TL;DR: Although AM can offer time and cost benefits under the correct conditions, among the more impactful demonstrations of the manufacturing technology are the novel topologies enabled by design rules that allow feature sets, including nonorthogonal planes, conformal surfaces, multimaterial deposition, simultaneous thick- and thin-film deposition, complex 3D structures, integrated voids, and gradient index materials.
Abstract: With the revolutionary developments in the fields of millimeter-wave (mm-wave) and Internet of Things (IoT) technologies and the billion devices promised to be implemented by the end of the decade, the realization of inexpensive, low-power, and intelligent systems is highly desirable. Additive manufacturing (AM) is a technology seeing widespread adoption due to its ability to enable rapid prototyping for iterative design; its reduced setup costs, facilitating economic small-batch production; and its ability to significantly reduce waste by-products, resulting in both environmental benefits as well as lower manufacturing costs. On the other hand, current lithography-based manufacturing technologies-a huge contributor to the growing RF and 5G wireless electronics industry-require extensive design verification, have longer turnaround times, and produce harmful byproducts. Although AM can offer time and cost benefits under the correct conditions, among the more impactful demonstrations of the manufacturing technology are the novel topologies enabled by design rules that allow feature sets, including nonorthogonal planes, conformal surfaces, multimaterial deposition, simultaneous thick- and thin-film deposition [1], complex 3D structures, integrated voids, and gradient index materials.
TL;DR: In this paper, the crystal structure of graphite, which consists of parallel carbon layers, is shown and a weak Van der Waals force exists between the layers due to the p-bond.
Abstract: "Graphene is the smallest possible thinness layer of graphite, with a thickness of 0.34 nm" [1]. It is made up of sp 2 hybridized carbon atoms in such a way that each carbon atom bonded is attached to three others in a covalent bond, as shown in Figure 1(a) [2]. One s orbital and two p orbitals ( p x, p y) together result in sp 2 hybridization with 120d angles between the hybrid orbitals, forming a s-bond. Figure 1(b) shows the crystal structure of graphite, which consists of parallel carbon layers. The perpendicular p z orbital to the sp 2 hybrid orbital forms a p-bond. A weak Van der Waals force exists between the layers due to the p-bond. In the past, it was theoretically studied as the building block of graphitic materials with other dimensions [3], [4]. Because of the weak Van der Waals forces between the stacked layers of graphite in graphene, isolated graphene was considered to be thermodynamically unstable and, thus, was thought not to exist in reality [5]-[7].
TL;DR: The next breed in ICT is closely related to, and enabled on a large scale by, the much-publicized 5G and future heterogeneous wireless systems, which in the future will connect everyone and everything at different speeds for various functions and services.
Abstract: Emerging and disruptive information and communication technology (ICT) RaD is principally driven by the growing needs of signal generation, collection, transmission, processing, and storage as well as the applications of massive data sets in our fast-evolving information society. Such data set-related operations call for fundamental wireless- and wireline-empowered capabilities as well as many others. The next breed in ICT is closely related to, and enabled on a large scale by, the much-publicized 5G and future heterogeneous wireless systems [1]-[4], which in the future will connect everyone and everything at different speeds for various functions and services. This will propel us toward a much more connected, smarter world.
TL;DR: The history of higher symmetries started much earlier as discussed by the authors, with the use of higher symmetry and reflection to produce unbelievable transitions and transformations of objects and beings, as illustrated in Figure 1(a).
Abstract: Higher symmetries frequently amaze human beings because of the illusions and incredible landscapes such symmetries can produce. For example, imagine the unearthly pictures of the Dutch graphic artist M.C. Escher. He made use of glide symmetry and reflection to produce unbelievable transitions and transformations of objects and beings, as illustrated in Figure 1(a). However, the history of higher symmetries started much earlier. Escher was partially inspired by the Moorish tessellations in the Alhambra in Granada, Spain, such as the ones pictured in Figure 1(b).
TL;DR: The demand for data communication capacity keeps increasing, and the common trend for high-speed wireless communication is to shift the operating frequency toward the millimeter-wave (mm-wave) spectrum and exploit the highly available bandwidth.
Abstract: The demand for data communication capacity keeps increasing. Applications ranging from wireless and hand-held mobile electronics to big data centers and backbone infrastructure are driving the need. With 5G technology being deployed, the common trend for high-speed wireless communication is to shift the operating frequency toward the millimeter-wave (mm-wave) spectrum (30-300 GHz) and exploit the highly available bandwidth. This shift is driven by the continuous improvement of bulk CMOS and packaging technologies that enable the full integration of mm-wave radios. Copper wireline technology also continues the trend toward multilevel and multitone modulation for high-speed, short-distance communication links. Copper cables, however, are often complex, expensive, and prone to electromagnetic interference (EMI). Moreover, the required equalization techniques are power hungry. Optical communication benefits from low-loss glass optical fibers (GOFs) with enormous bandwidths, enabling trans-Atlantic communication. This technology, however, requires micrometer alignment precision and costly optical-electrical conversion.
TL;DR: Currently, artificial satellites are extensively used for scientific, military, and civil applications, particularly for telecommunications satellites.
Abstract: Currently, artificial satellites are extensively used for scientific, military, and civil applications, particularly for telecommunications satellites.
TL;DR: Each generation of mobile devices demands a larger number of RF filters and switches, and, with the transition toward 5G and its corresponding frequency bands, the large number of required filters will only add to the challenges associated with cell-phone RF front-end design.
Abstract: Wireless communication has become an integral part of our lives, continuously improving the quality of our everyday activities. A multitude of functionalities are offered by recent generations of mobile phones, resulting in a significant adoption of wireless devices and a growth in data traffic, as reported by Ericsson [1] in Figure 1. To accommodate consumers' continuous demands for high data rates, the number of frequency bands allocated for communication by governments across the world has also steadily increased. Furthermore, new technologies, such as carrier aggregation and multiple-input/multiple-output have been developed. Today's mobile devices are capable of supporting numerous wireless technologies (i.e., Wi-Fi, Bluetooth, GPS, 3G, 4G, and others), each having its own designated frequency bands of operation. Bandpass filters, multiplexers, and switchplexers in RF transceivers are essential for the coexistence of different wireless technologies and play a vital role in efficient spectrum usage. Current mobile devices contain many bandpass filters and switches to select the frequency band of interest, based on the desired mode of operation, as shown in Figure 2. This figure presents a schematic of a generic RF front end for a typical mobile device, where a separate module is allocated for the filters. Each generation of mobile devices demands a larger number of RF filters and switches, and, with the transition toward 5G and its corresponding frequency bands, the larger number of required filters will only add to the challenges associated with cell-phone RF front-end design.
TL;DR: The three key concepts of modern microwave-filter synthesis using coupled resonators: coupling matrix (CM), extracted pole (EP), and nonresonating node (NRN) are reviewed in this paper.
Abstract: This article reviews the three key concepts of modern microwave-filter synthesis using coupled resonators: coupling matrix (CM), extracted pole (EP), and nonresonating node (NRN). CM synthesis is no doubt the most popular and powerful of the three. EP has been around longer as a circuit-synthesis tool, but it seems to have only limited applications. Both CM and EP were developed before the proliferation of electromagnetic (EM) simulators and fast modern computers. CM is widely used because the simple mapping relationship between the physical dimension of coupling structures and synthesized coupling values is well developed. NRN is the newest concept and has drawn a lot of attention. It is a result of circuit synthesis but can also be expressed using CM/EP.
TL;DR: In the frequency ( f ) regime of interest for microwave engineers, there exist three (one longitudinal, two shear) branches of vibrational modes with long wavelengths as mentioned in this paper, and the ratio between the two is typically several kilometers per second.
Abstract: Atoms in all materials are constantly shaking, which is largely responsible for the transfer of heat and sound. In a uniform crystalline solid, the motion of the lattice can be decomposed into just a handful of normal modes of vibration or, in the language of quantum mechanics, a set of quantized eigenmodes of the elastic structure known as phonons [1]. In the frequency ( f ) regime of interest for microwave engineers, there exist three (one longitudinal, two shear) branches of vibrational modes with long wavelengths-"long" when compared with the atomic spacing. Their frequencies, which represent the energy of each quantum, are linearly proportional to the inverse wavelengths, which represent the momentum of each quantum. The ratio between the two is typically several kilometers per second. In good crystals with few imperfections, these vibrations travel a very long distance-"long" when compared with the wavelength-with little decay of the amplitude under the ambient temperature and pressure. At audio frequencies, these sound waves can propagate in solids. They are commonly known as acoustic waves (see "Nomenclature Used Throughout").
TL;DR: Strategies for estimating the parameters controlling the DPD linearizer are reviewed.
Abstract: Digital predistortion (DPD) is the linearization technique most often used to cope with the inherent tradeoff between linearity and efficiency in power amplifiers (PAs). Adaptation is needed to optimize DPD performance. This article reviews strategies for estimating the parameters controlling the DPD linearizer.
TL;DR: In this paper, an opaque screen with a 10-nm diameter pinhole within 10 nm of the sample was used to obtain subwavelength resolution of a biological sample, regardless of the wavelength of the light.
Abstract: Often, a student comes in excited by a revolutionary idea. When this happens, we invite the student to check the literature carefully and, moreover, to extend the search way back, for more than a century, in fact. For example, encouraged by Albert Einstein, Edward H. Synge introduced the concept of a near-field scanning microscope in the 1928 paper "A Suggested Method for Extending Microscopic Resolution Into the Ultramicroscopic Region" [1]. He claimed to have overcome the "...axiom in microscopy, that the only way to extend resolving power lies in the employment of light of smaller wavelength." For subwavelength resolution of a biological sample, Synge proposed to place an opaque screen with a 10-nm diameter pinhole within 10 nm of the sample (Figure 1). Light passing through the pinhole and the sample is focused on a photodetector. By moving the screen laterally in 10-nm steps, the sample is imaged with 10-nm resolution, regardless of the wavelength of the light. Later, what he proposed became known as a scanning near-field optical microscope (SNOM) .
TL;DR: Substrate integrated waveguide technology is a well established and successful approach for implementing planar microwave filters with very stringent requirements in terms of quality (Q) factor and also with the ability to integrate into a system.
Abstract: Substrate integrated waveguide (SIW) technology [1], [2] is a well established and successful approach for implementing planar microwave filters with very stringent requirements in terms of quality (Q) factor and also with the ability to integrate into a system. Optimized SIW filters can reach a Q factor of 200-800 using low-loss substrates and standard fabrication procedures [3]. Furthermore, packaging and electromagnetic (EM) shielding, power-handling capabilities, and low-cost batch manufacturing are other broadly recognized strengths of this approach. However, SIW filters are still larger than most of their planar counterparts; in addition, advanced topologies are not always easy to accommodate, and filter reconfigurability usually leads to very complex implementation [4]-[6].
TL;DR: SDR is a promising radio technology to increase the flexibility of radio devices and reduce hardware and manufacturing costs, chip size, and power consumption and is proposed to handle multiple bands through reconfiguration.
Abstract: The last decade has witnessed an increasing number of wireless standards for civil, military, and space communications. Along with the advances in integrated circuit (IC) technologies and the ever-growing requirements of high data rates, next-generation radios are expected to operate over multiple frequency bands. For example, carrier aggregation is used in LTE-Advanced radios to increase the bandwidth. However, it is challenging for traditional radios to operate over multiple frequency bands. In response to this, software-defined radios (SDRs) have been proposed to handle multiple bands through reconfiguration. They can adapt carrier frequency, transmission bandwidth, modulation, and encoding schemes by modifying digital signal processing (DSP) software algorithms [1]. In contrast to SDR, legacy communication systems are approaching their capability limits. They usually operate on a single band and require dedicated hardware. Thus, SDR is a promising radio technology to increase the flexibility of radio devices and reduce hardware and manufacturing costs, chip size, and power consumption [2].
TL;DR: This report suggests that an investment of roughly US$130-150 billion could be required over the next seven years, given that the current infrastructure is not adequate to support the expected growth in wireless data.
Abstract: According to a recent report [1], the United States is expected to see a fourfold increase in mobile data traffic between 2016 and 2021. Notably, the report suggests that an investment of roughly USd130-150 billion could be required over the next seven years, given that the current infrastructure is not adequate to support the expected growth in wireless data. Further, current transceiver architectures [2] are bulky, inefficient, and expensive.
TL;DR: Carrier aggregation is a technology first introduced in LTE-Advanced (LTE-A) to increase the peak data rate of 4G networks and will continue to be widely and intensively used in future-generation communications, such as 5G.
Abstract: Carrier aggregation (CA) is a technology first introduced in LTE-Advanced (LTE-A) to increase the peak data rate of 4G networks (for example, the maximum available speed) [1]. The mobile network operator can increase the total available bandwidth for a single user by aggregating multiple channels together, thereby increasing the user data rate as well as the spectrum utilization efficiency and resource allocation flexibility of the entire network. Before LTE-A, mobile network operators could allocate the spectral resource only to a particular user within a single designated frequency band, limiting the maximum channel capacity. The realization of CA allows network operators to create larger channels from nonadjacent spectrum blocks. For example, operators can use a 10-MHz carrier from the 2,100-MHz band and combine it with another 5-MHz carrier from the 700-MHz band to create a 15-MHz LTE channel. The LTE-A standard specifies that each of the component carriers (CCs) of the communication signal is limited to 20 MHz of bandwidth. Aggregation of up to five CCs allows a maximum of 100 MHz of total signal bandwidth, as depicted in Figure 1. This leads to a fivefold increase in channel capacity and data speed [2]. It is projected that CA technology will continue to be widely and intensively used in future-generation communications, such as 5G.
Abstract: The optical characterization of nanoscale objects is challenging due to the Abbe diffraction limit. This limit constrains the achievable spatial resolution of a conventional microscope using visible light to a 200 nm . 200 nm. The current era of nanotechnological research has been enabled by a host of experimental techniques that circumvent the diffraction limit. Since the Abbe limit scales proportional to the wavelength of electromagnetic radiation, the diffraction limit acts even more unfavorably on longer wavelengths. At 10 GHz (l = 30 mm), the best achievable resolution is around 15 mm. Thus, while traditional microwave metrology enables precision broadband measurements, conventional measurement methods are insufficient to address the host of novel and exciting phenomena that arise in nanoscale systems.
TL;DR: In this paper, the authors proposed a multifunctional filtering circuit, including passive and active circuits, to reduce the loss and size of the whole system, which can be codesigned as multifunctional filter circuits.
Abstract: The rapid development of wireless technologies has created high demand for microwave circuits with compact size, low loss, and high efficiency. Bandpass filters (BPFs) are essential in wireless systems, which are cascaded with many circuits in RF front ends, i.e., power dividers [1], couplers [2], switches [3], and power amplifiers (PAs) [4]. They can be codesigned as multifunctional filtering circuits, including passive and active circuits, to reduce the loss and size of the whole system.
TL;DR: This work hopes to provide an instructive introduction to the control, signal generation, and distribution principles currently used in small quantum systems that operate in the microwave frequency regime.
Abstract: Let's boot up a quantum computer. Far from being a simple push of a button, initializing a prototype quantum computer requires the precise tuning and calibration of many different parameters. Rather than switching transistors on and off, the controller of a quantum processor emits combinations of analog waveforms, each with a characteristic shape, frequency, and duration. These waveforms are used to either manipulate or read out the states of quantum bits (qubits), the basic units of quantum information in the processor. The analog nature of the system inherits many of the complexities of analog computing, including device parameter drift and offsets, system component tolerances and variabilities, and other well-known analog-circuit intricacies. Further, de livering these signals to the target qubits necessitates coordination between multiple low-noise and low-jitter instruments. In spite of these challenges, the quantum computing community has made tremendous progress toward useful quantum machines. We hope to provide an instructive introduction to the control, signal generation, and distribution principles currently used in small quantum systems that operate in the microwave frequency regime.