FEATURE MILITARY, AEROSPACE & DEFENCE
• LTCC Technology: L pass filter design is based on five layer LTCC technology
• QFN Packaging and Microstrip Technology: Standard QFN package technology is used for PA, LNA and SPDT switch packaging. All these design modules are
integrated into a single system-on- board chip. Design and simulation of complete transceiver systems are very challenging due to the presence of multiple technologies in one single design. So, the Advanced Design System (ADS) Finite Element Method (FEM) based electromagnetic solver is used to analyse the complete module. A peak module output gain of 18.2 dB is achieved with an overall module efficiency of 21%. The performance of the complete system is analysed using FEM simulated data and circuit components using schematic co-simulation in ADS. The topology used in this system improves the system performance and reduces the chip size. The transceiver system is applied in an active phase array to demonstrate beam sequencing with a variation of phase values.
SAR ARRAY ANTENNA DESIGN The synthetic aperture radar (SAR) is a microwave imaging system that can produce a high-resolution image of the Earth. Here, simulation tool capability and the way tools are used play an important role in design cycle time and cost. This design technology reduces total design iteration time significantly. Three different EM solvers are used efficiently for component level and integrated antenna design. SAR antenna is a multilayer Microstrip
stack of 8x8 arrays with 5.2 GHz centre frequency. This antenna operates at very high peak power of 6KW and PRF 1.2% and 1:8 square coaxial feeder networks are used to handle the high power demand of antenna. This is a complex design and it is very difficult to simulate a complete system using a single electromagnetic solver. A mixed electromagnetic simulation
technique is used to simulate this array antenna that reduces the design cycle by 50%. Radiating array are planar in nature so this is realised using a 3D-planar Momentum EM solver and high power Square-Coaxial-Line (SCL) feed network of the antenna is designed using FEM electromagnetic solver. This project is very large for
simulation but by applying iterative solver and mesh refinement techniques, simulation time has been reduced by 40%. After optimising the radiating element and feed network separately, the complete integrated antenna system is simulated with the
24 JULY/AUGUST 2016 | INSTRUMENTATION
FDTD (Finite Difference Time Domain) solver. FDTD simulation can handle much bigger designs compared to the FEM solver.
MULTI-MODE FEEDER NETWORK The design of a multimode extractor for the feed chain of monopulse tracking feed used for earth station antenna at Ka band is given here. This is a new concept to extract the first five higher order modes of a circular waveguide. The multi-mode extractor couples first five circular waveguide propagation modes TE11, TE110
(TE11 orthogonal mode), TM01, TE21, and TE210 (TE21
orthogonal mode), that includes the three tracking signals (i.e. sum signal, elevation signal, and azimuth signal) used in a high-frequency monopulse tracking system, and two communication channels for transmitting and receiving signal at the Ka band. This design is based on amplitude and phase characteristics of the higher- order modes TM01, TE21, and TE210 excited in a circular waveguide. TE21 and TE210
mode are extracted from
circular waveguide to TE10 mode in the rectangular waveguide by two longitudinal slots milled in the circular waveguide. TE11 mode is coupled using two coupling slots and an H-plane power combiner. A turnstile junction is used to extract TM01 and TE110. This multimode tracking system is designed for ground earth station antennas to track orbiting satellites. As this is a complex design, the
complete design has been simulated through a Finite Difference Time Domain Technique using a GPU card. Finite difference methods are widely used highly parallel algorithms for solving deferential equations. To improve the method’s calculation speed and realise large-scale computing with the numerical complex model, a multi-GPU environment using Compute Unified Device Architecture (CUDA) is used. The calculation speed with four GPUs was approximately 20 times faster than with a CPU. The simulated return loss and insertion loss characteristics of this hardware have been found to be better than –20 dB and 0.4 dB insertion loss over 0.25% frequency band around 29.3, as shown in Figure 3.
SIGNAL INTEGRITY CHALLENGES SATA and USB 3.0 connectors are used in the backplane to transfer satellite remote sensing data to servers. Signal integrity (SI) analysis of these high-speed interconnects integrated with RF board differential line traces is carried out by applying 3D electromagnetic simulation along with transient circuit solver. High-speed digital design, such as
multiple power and ground planes, different IO chips and high-speed connectors, requires improvement of integrated circuit operating speed and density. One of the major challenges in these techniques is impedance discontinuities that induce signal integrity (SI) and electromagnetic interference effects if you simulate boards and connectors separately. Full-wave 3D electromagnetic numerical analysis of high-speed and high-density interconnects along with high-speed board traces is a great challenge. This electromagnetic simulation
approach provides a new process for such 3D component simulation as connectors using Finite Element Method (FEM) solver and board designs using a Method-of-Moment (MoM) based electromagnetic solver. The SATA-to- USB module is characterised by reflections, crosstalk, and power plane noise coupling problems to a data signal that can cause the false signal transition. The design process demonstrates a unique methodology to reduce design production time significantly. Post-layout signal integrity analysis
including the connectors and RF board is performed to know waveform quality, crosstalk and timing for system-level design. In this project, instead of using separate S-parameter blocks of RF board and connectors for SI analysis, integrated RF boards along with high-speed USB and SATA connects are applied for channel simulation. SI analysis on an integrated system gives accurate answers and avoids error-prone and time-consuming measurements. A channel simulator is used to check
Figure 3. Simulated electric field coupling of all five modes and radiation
EYE opening of the complete channel in ADS. The channel simulator accounts for encoding, equalization and crosstalk to high-speed digital designers. The Eye Probe gives an accurate analysis of eye diagram properties including BER contours, mask compliance, width, density and height. Channel insertion loss is mainly dependent on system impedance profile, the material used and impedance mismatch, and crosstalk is created by capacitive or inductive between signal paths.
Keysight
www.keysight.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64