Common RF test platform

The development of a PC-based functional test platform that incorporates Statistical Process Control (SPC) and a failure analysis database is described. With Commercial Off-The-Shelf(COTS) tools available it is possible in a low volume high-mix environment to easily obtain basic statistical information on each test, develop an easily accessible database of information on failures, causes of failures and troubleshooting activities and increase test efficiency with minimal test development costs. A common test platform has been developed that can be configured to test a wide variety of sub-assemblies from digital controller cards to radio frequency (RF) modules. The platform consists of a PC with a multi-function data acquisition card and a General Purpose Interface Bus (GPIB) card for control of test instruments. Applications are linked with Dynamic Data Exchange (DDE) and the PCs are connected to the company's Local Area Network (LAN) so that test data can be accessed from throughout the plant. A key point is the implementation of SPC with this test platform. Statistics include process capability indices C/sub p/ and C/sub pk/ and failure rate. Test data is analyzed and used to make process improvements. Examples are presented. Since the entire system has been designed and built around established COTS software and hardware, additional capabilities can be easily added in the future. Some planned enhancements are described.

Software-defined radio (SDR) is an emerging technology that offers various advantages over conventional radio designs. The SDR approach uses a common hardware platform, programmed by software modules and firmware, to support many communications standards and operating frequencies. The technology is being promoted by the US Department of Defense to replace tens of thousands of single-protocol, single-purpose radios with a common platform. Military and public safety organisations worldwide are also considering this technology to solve interoperability problems enabling, for example, police and firefighters to easily communicate in the field. In addition, the commercial wireless industry views SDR as a means of reducing development cost and time to market. To fully realize SDR’s promise of an all-encompassing communications device capable of transmitting and receiving over a very wide frequency range requires special attention to the radio frequency (RF) transceiver. Although it is relatively easy to use conventional electronics to build SDRs operating at up to 6GHz, it is increasingly difficult to do so at higher operating frequencies. It needs a hardware platform capable of operating up to about 60GHz to take full advantage of the SDR concept. Ideally, the SDR hardware platform has a continuouslytunable source to act as a local oscillator. It should be possible to modulate this source in any format, perform signal conditioning, and distribute the signal: either by wireless transmission or over an optical network. The prospect of using conventional electronics to develop a commercially-viable source with these properties is limited, so it may be necessary to find another approach. Optical technology can emulate many of the functions normally associated with RF reception and transmission. For example, it is possible to generate microwave signals optically over a very large frequency range—from MHz to THz—using heterodyne techniques such as optical injection locking, optical phaselocked loops, and nonlinear up-conversion. The electrical RF signal is generated by shining two optical inputs, separated by the desired microwave frequency, on to a square-law photodetector that acts as a mixer and generates their beat frequency. In general, when no phase or frequency control is applied, the phase noise of the microwave signal is approximately equal to the sum of the optical linewidths. The key to reducing this typicallyMHz linewidth down to values that are more practical for a communications system is to ensure that the phases of the optical signals are highly correlated. If they are, a very narrow RF linewidth can be achieved, even from large-linewidth optical sources. A carrier is of limited use in a communication system without some form of encoded information. A laser source can be modulated by inserting a baseband optical modulator in the optical path, or by other means. The modulation formats are varied and may act on the frequency, amplitude, or phase of the signal. In general, the bandwidth of the modulator/demodulator is dictated by the format of the protocol or the radio-spectrum channel allocation and is relatively modest, since the high-frequency carrier is already optically generated. This means that digital demodulation can be done directly by the computer, after optical down-conversion, to make it easier to interface with the SDR software. Both the receiver and transmitter need RF filtering for signal conditioning. Techniques for electrical filtering in the optical domain have been examined extensively, but the all-optical microwave filters proposed to date are primarily based on incoherent manipulation of optical carriers with only positive taps. This approach can only create low-pass filters. Many applications, including SDR systems, need bandpass and flat-top filters as well. To overcome this limitation, Yao et. al. recently reported a way to build an all-optical microwave bandpass filter with a simple structure.

The manufacturing and test of avionics products for military and commercial aircraft presents a unique set of requirements and challenges. Historically, the development and deployment of production test systems for avionics products such as aircraft data acquisition and recording systems, navigation and communication products, and aircraft network systems have been addressed on a product specific basis - resulting in a variety of test platforms and solutions with little test system commonality and technology. Additionally, this lack of test system commonality and the requirement to maintain legacy products with long product life cycles results in increased maintenance and logistics costs for manufacturing and support test. Consequently, the adoption of a common test platform can offer producers of avionics products lower test costs, improved test resource utilization, and the flexibility to support both new and legacy products. This paper reviews the requirements and the implementation of a common test platform and environment that offers a high level of efficiency, supports the implementation of routine test processes, offers reusability, and allows the consolidation of test resources to facilitate the collection of reliability data and test results.

This article presents a monolithically integrated reflective-type phase shifter (RTPS) utilizing silicon-on-insulator (SOI) radio frequency (RF) microelectromechanical systems (MEMS). The analog phase shifter employs a hybrid coupler and two identical reflective loads optimized to achieve a large phase shift range. The hybrid coupler is designed using two CPW-based couplers connected in a folded tandem configuration to achieve a compact size design. Various reflective load topologies are studied for optimum phase shift range and phase linearity over the bandwidth of interest. Measurement results demonstrate a continuous 120° tunable range from 26 to 30 GHz. The mmWave phase shifter exhibits a low insertion loss of 5.35 dB ± 0.6 dB at 28 GHz. The fabricated phase shifter has an overall device footprint of 4.0 mm × 2.6 mm. All the components of the phase shifter module are co-fabricated in the 20 μm device layer of a SOI wafer, which provides the flexibility of monolithic integration with other RF modules in phased array antenna systems. Contactless thermally actuated MEMS varactors are used in the reflective loads which do not suffer from the conventional contact-based reliability issues.

This paper proposes an on-chip six-port reflectometer (SPR) fabricated in the 0.13-μm IBM BiCMOS-8HP technology. The SPR enjoys a compact circuit structure, with only four amplitude detectors as active devices, one resistive power divider, and one lumped phase shifter as passive devices. The power divider and phase shifter are responsible for manipulating the radio-frequency (RF) signals appropriately, whereas the detectors are responsible for sensing the processed signals. The chip area, which can be further reduced, is 1.25 mm in width and 1 mm in height. The SPR can perform in-situ measurement of reflection coefficients of devices under test (DUTs) and reduce testing costs of RF chips by using vector network analyzers (VNAs). The SPR demonstrates excellent performance in measuring the reflection coefficients of DUTs at around 20 GHz. The experimental results indicate that the maximum error of the measured reflection coefficients in absolute value is about -26 dB.

Radio frequency (RF) MEMS is an emerging sub-area of MEMS technology that is revolutionizing RF and microwave applications. RF MEMS devices have a broad range of optional applications in military and commercial wireless communication, and navigation and sensor systems. This article presents the EM design of different multiport toggle switches. Such a multiport switch can be used in the compact designs of switching matrices, routing networks, or phase shifters. One application range is the creation of electronically steerable antenna arrays, which can be used for radar applications and satellite communication. The miniaturized switches are based on the single pole single throw (SPST) toggle switch and, in addition to their small size, they have an increased RF performance regarding losses and operation bandwidth (DC to 50 GHz). A 3D FDTD field solver has been used for the electromagnetic design of all the switches. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14: 329–337, 2004.

The development of a thick-film hermetic BGA package for a radio-frequency (RF) microelectromechanical systems (MEMS) 2-bit phase shifter is presented. The measured packaged MEMS phase shifter average in-band insertion loss was 1.14 dB with an average return loss of 15.9 dB. The package transition insertion loss was less than 0.1 dB per transition with excellent agreement between simulated and measured results. It was also demonstrated that the RF MEMS phase shift performance could be improved to obtain a phase error of less than 3.3 degrees. The first reported measurements of the average rise and fall times associated with a MEMS circuit (in this case a 2-bit phase shifter) were 26 and 70 /spl mu/s, respectively. The advent of packaged RF MEMS phase shifters will reduce the cost (both design and building) of future phase arrays.

This dissertation investigates the use an array of active nonlinear elements, with particular emphasis on controlling distortion products generated by nonlinear elements in space rather than using conventional ways such as transmission lines, waveguides, and power dividers and combiners. The nonlinear elements are made of assemblies of antennas and electronic switches, called modulated scatterers (MSs). These so-called MSs elements are utilized in a wide variety of applications such as radio frequency identification (RFID) systems, microwave imaging, Internet-of-Things sensors, etc. However, no research work has been reported in the literature regarding exploiting and controlling several distortion products generated by MSs at the same time according to the best of authors' knowledge. To facilitate controlling distortion products which means suppressing or enhancing distortion products in space, we present a nonlinear array with elements that are MSs instead of conventional antennas. MSs are switched ON-OFF at different times by modulation signals having the same frequency. The time delay of the switching process between array elements represents a relative phase shift difference in the frequency domain. Thus, the presented structure is called the phase-modulated scattering array (PMSA). The PMSA has a similar layout of phased arrays, but it does not have a feeding network and is fed by an external source called the illuminating source. Because our system does not need a feeding network and phase shifters, it is potentially easier to implement with low cost. Two different signals which are the illuminating (incident) and modulation signals interact inside switches to generate a huge number of distortion products due to the nonlinearity of switches and the periodic nature of the presented system. Distortion products then leave the presented PMSA to space again (i.e., scattering distortion products). The PMSA is able to treat distortion products and achieve beamforming functions. The operation mechanism of the PMSA is explained by developing two different mathematical models. Communication signal processing perspectives are the basis of the first mathematical model developed to show the spatial characteristics of distortion products generated by our presented PMSA. Its root is originated from a mathematical model of the widely-used polyphase multipath technique in RF communication circuits. However, the adopted technique is suitable only for communication circuits with a single output and parameters prescribed in advance. Thus, the model is further developed to circumvent all the problems mentioned above and to be able to detect the spatial characteristics of distortion products at any point in

A novel integrated photonic radio frequency (RF) phase shifter using a dual-drive Mach-Zehnder modulator is proposed. This RF phase shifter has a simple configuration and is fabricated easily. The simulated results show that this device has excellent performance in shifting phase. It is expected that this RF phase shifter will find widespread applications in optically controlled phased array systems and optical fiber communication systems.

An all-optical photonic microwave phase shifter that can realize a continuous 360° phase shift over a wide frequency range is presented. It is based on the new concept of controlling the amplitude and phase of the two RF modulation sidebands via a Fourier-domain optical processor. The operating frequency range of the phase shifter is largely increased compared to the previously reported Fourier-domain optical processor based phase shifter that uses only one RF modulation sideband. This is due to the extension of the lower RF operating frequency by designing the amplitude and phase of one of the RF modulation sidebands while the other sideband is designed to realize the required RF signal phase shift. The two-sideband amplitude-and-phase-control based photonic microwave phase shifter has a simple structure as it only requires a single laser source, a phase modulator, a Fourier-domain optical processor and a single photodetector. Investigation on the bandwidth limitation problem in the conventional Fourier-domain optical processor based phase shifter is presented. Comparisons between the measured phase shifter output RF amplitude and phase responses with theory, which show excellent agreement, are also presented for the first time. Experimental results demonstrate the full -180° to + 180° phase shift with little RF signal amplitude variation of less than 3 dB and with a phase deviation of less than 4° over a 7.5 GHz to 26.5 GHz frequency range, and the phase shifter exhibits a long term stable performance.

The test of microwave semiconductor chip is currently a hot topic. A miniaturized and highly integrated RF (Radio Frequency) module is designed to test microwave semiconductor chip. Similar to the design concept of synthetic instrument which has an open structure with standard bus and software defined radio, the newly designed integrated RF channel technology realize a variety of RF testing functions. It provides a small and highly integrated common hardware platform with a flexible software platform for re-development of control software. This platform is highly integrated with vector signal generation, vector signal analysis, vector network analysis and noise figure analysis, which can achieve a variety of functional test through dynamic reconfiguration and real-time loading. Multi-stage switch and coupler network are used to route reference signals and reflected signals and transmit signals for vector network analysis. The module receives and generates signals with frequency covering 100k~18GHz. It shares baseband FPGA which makes received signals simultaneously replay in generated channels. The bandwidth reaches 500MHz and supports a variety of vector modulated standards. This module provides a perfect solution to the testing system for microwave semiconductor chip.

A simplified design method has been proposed for systematic design of novel radio frequency (rf) power combiner and divider, incorporating radial slab-line structure, without using isolation resistor and external tuning mechanism. Due to low insertion loss, high power capability, and rigid mechanical configuration, this structure is advantageous for modern solid state rf power source used for feeding rf energy to superconducting accelerating structures. Analysis, based on equivalent circuit and radial transmission line approximation, provides simple design formula for calculating combiner parameters. Based on this method, novel 8-way and 16-way power combiners, with power handling capability of 4 kW, have been designed, as part of high power solid state rf amplifier development. Detailed experiments showed good performance in accordance with theory.

Hardware-in-the-Loop (HIL) simulation technique provides a solution to perform tests without risking damage to Line-Replaceable-Unit (LRU) and reduce costs via increasing the speed of continuous verification and validation. As an important part of verification and validation phase of a system, the Hardware-in-the-Loop simulation is one of the most effective techniques for an LRU system testing and makes a substantial contribution in avionics model integration process and realization of the system. Based on the Hardware-in-the-Loop simulation method, this paper designs the structure and parameters of a Hardware-in-the-Loop simulation test system for an indigenous flight control computer system test. This test system comprises of plant models, signal generation module, data acquisition module, record module, switching module for signal loss and error injection scenarios, and a graphical user interface. Test system includes a Peripheral Component Interconnect Extension for Instrumentation (PXI) chassis with a real-time operating system, hardware capable of converting the digital signals generated by an aircraft model into analog signals proper to LRU input signals and transmitting to LRU, also hardware capable of converting the digital signals generated by the flight control computer into analog signals to the control model and, moreover a recording unit in which all these signals are logged in parallel with data acquisition process.

Precoding/combining and large antenna arrays are essential in millimeter wave (mmWave) systems. In traditional MIMO systems, precoding/combining is usually done digitally at baseband with one radio frequency (RF) chain and one analog-to-digital converter (ADC) per antenna. The high cost and power consumption of RF chains and ADCs at mmWave frequencies make an all-digital processing approach prohibitive. When only a limited number of RF chains is available, hybrid architectures that split the precoding/combining processing into the analog and digital domains are attractive. A previously proposed hybrid solution employs phase shifters and mixers in the RF precoding/combining stage. It obtains near optimal spectral efficiencies with a reduced number of RF channels. In this paper we propose a different hybrid architecture, which simplifies the hardware at the receiver by replacing the phase shifters with switches. We present a new approach for compressed sensing based channel estimation for the hybrid architectures. Given the channel estimate, we propose a novel algorithm that jointly designs the antenna subsets selected and the baseband combining. Using power consumption calculations and achievable rates, we compare the performance of hybrid combining with antenna switching and phase shifting, showing that antenna selection is preferred in a range of operating conditions.

This paper deals with the RF (Radio Frequency)-MEMS (Micro-Electro-Mechanical-System) switches are integrated in CPW topology. Phase shifter is integrated on high resistivity silicon substrate and loading elements are 360 switch design using the coventorware software and its superiority over the existing technologies like PIN Diodes and Field-Effect-Transistors regarding size, power, Isolation The measured down state insertion loss of ?0.1 dB up to 40 GHz and switch resistance is 1 ?. The measured reflection coefficient is dominated bt t-line switch is ?20 dB at 30 GHz. This switch used in X-band and K-band phase shifter, switched capacitor bank and tunable filter. The 1-kg class satellite plans to use the MEMS TxRx switch as a functional component on its RF communication board. Application of switch based Phase shifters for satellite based radars (20 billion cycles), missile systems (0.1---1 billion cycles), long-range radars (20---200 billion cycles). By cutting the mass of components onboard the space vehicle, the launch costs and hopefully the overall budget for production can be reduced.