Conferences

3D EM and thermal simulation for RF system in package

The design and optimization of high-performance RF systems and packages require accurate simulation models that can capture the behavior of the device under different operating conditions. This paper presents an approach that combines 3D electromagnetic (EM) simulation with High-Frequency Structure Simulator (HFSS) and thermal simulation with Icepacke to model the behavior of RF system in packages. The 3D EM simulation allows for accurate modeling of the device's electromagnetic behavior and the thermal simulation predicts the temperature distribution in the device and its package. The importance of 3D EM simulation is highlighted, as traditional 2D simulations are no longer sufficient to capture the full complexity of modern RF devices. By combining 3D EM simulation with thermal simulation, the proposed approach provides a more accurate representation of the device's behavior under different operating conditions. The proposed approach provides valuable insights for design engineers looking to optimize the performance of high-power and high-efficiency RF systems and packages for various applications.

Automated Measurement and Evaluation of 6-bit Amplitude and Phase Control Modules

Vector modulators can be used in the design of phased array antennas and in feedforward linearization systems. This paper presents the automated testing of an S and C band 12-bit vector modulator, which uses a 6-bit phase shifter and 6-bit attenuator to vary signal phase and amplitude. A Python program was written to automate the testing of all 4096 possible states, to better understand the potential performance of the vector modulator. The combined performance is presented and is examined outside the respective frequency ranges of each device. This paper outlines the technical challenges faced in performing and processing the measurements and highlights the advantages of an automated test setup.

Design and Testing of an FR-4 based Reference PCB for use in Environmental Conditioning

A 4-layer Reference Printed Circuit Board (PCB) is designed that features RF structures and standards used to evaluate the performance before, during and after Environmental Conditioning. The design aims to emulate the operating environment of a sub-6 GHz PCB found in Industry and uses a popular FR-4 substrate throughout the PCB’s stack up (Isola 370 HR). S-Parameter Measurements of the reference PCB’s RF elements are performed to establish a performance benchmark prior to submission to Environmental Conditioning. These measurements are then evaluated against simulation data to determine how effective the design implementation is.

Evolution of the Wafer-level Characterization Solutions: Towards mmW 6G Applications

In this presentation, we will briefly review the evolution of mmWave instrumentation and how it enabled complex characterization tasks at the wafer-level. We will look into the challenges and drivers of the 6G applied research and related technologies, such as instrumentation versatility, probe system integration complexity, broadband RF probes, calibration solutions, and metrology aspects. We will discuss possible system integration solutions and present selected measurement results for broadband single-ended and differential characterization.

Milimeter-wave load-pull measurment of GaN HEMT: driving the next generation of advanced power amplifiers

Power Amplifiers (PAs) remain a crucial component in the high frequency front-end of all wireless systems.  The increased interest in millimetre-wave frequency bands for a variety of applications posing more new challenges to device manufacturers and circuit designers.   GaN HEMTs can help addressing some of these challenges as they lead to high power PAs with better efficiency compared to other technologies.

The UK has a rich habitat in the microwave sector; from small design houses to large multinationals providing PA design services and products, and there are increasing investments to try and establish a sovereign source of GaN HEMT technology.  The success of this venture heavily depends on the availability of experimental characterisation capabilities, with load pull being the ultimate tool in this context for supporting both the foundries, with detailed information on the devices being developed, and the designers, by supporting accurate large-signal modelling.

Cardiff University and the CSA Catapult have a comprehensive provision of load-pull characterisation options.   This paper will discuss three of the measurement systems available, all capable of harmonic load pull and pulsed RF and bias, with passive implementations up to 110 GHz, and active up to 67 GHz, through three measurement campaigns on different GaN technologies supporting advanced PA design (harmonically tuned, Doherty) for up- and down-link satellite frequencies.

Realization of Switched SAW Filter Banks

The design of integrated switched Surface Acoustic Wave (SAW) filter banks as a capable solution to achieve high-performance multi-channel filtering solutions in VHF- to S-band with small size and weight is presented.

Modern communication systems in Aerospace & Defense and Industrial applications, frequently based on Software-Defined Radio (SDR) architectures, are increasingly using frequency hopping techniques for flexible selection of RF transmit and receive bands to minimize interference with other transmitters. To achieve robust connectivity of an SDR under all environmental conditions, powerful filtering solutions in the Radio Frequency (RF) front-end are usually considered necessary. Besides tunable filter realizations, which typically suffer from poor transitions between pass band and stop bands, switched filter banks in various technological realizations have been established solutions to support this requirement for years. To resolve the common drawback of large size and weight for electro-magnetic filter realizations in VHF- to S-band frequency ranges, miniature SAW filter banks have been developed allowing for tremendous size reduction in combination with the well-known high Q-factor of microwave acoustic filter solutions.

This paper describes the design constraints of multi-channel switched SAW filter banks, the challenges in electro-magnetic, SAW and thermal design of miniature filter bank solutions and presents selected realizations.

Simulating Process Variation Impact on the Performance of a mm-Wave Patch Array Antenna

Millimeter-wave structures and circuits are susceptible to performance degradation due to fabrication tolerances. To avoid multiple fabrication iterations due to such unaccounted effects, it becomes imperative that the impact of process variations is taken into consideration during the design and simulation phase. This paper presents the use case of an E-Band microstrip patch antenna array’s design, along with its simulation and measurement results, to demonstrate this scenario. This 4×4 antenna array was designed to operate in the 76-77 GHz frequency band and has a simulated -10 dB impedance bandwidth of around 2.4 GHz. As commonly seen with millimeter-wave designs, the post fabrication S11 measurements of this antenna showed a noticeable shift in its frequency response as compared to the simulated results. Here, Keysight’s ADS RFPro full 3D EM simulation software was utilized to effectively predict the impact of manufacturing tolerances on the desired performance of the antenna. Parametric process variation simulations in RFPro revealed that there was an under-etching of copper on the printed circuit board during fabrication. This potentially resulted in changes to the physical dimensions of the individual radiating patches, thereby resulting in a downward shift of the resonant frequency. These simulation results are further validated by means of measurements.