IN MY OPINION

Future Sparkles for Aluminum-Diamond Heat Spreaders
By Nano Materials International Corp. (NMIC)

About three years ago, I published an article in MPD describing aluminum-diamond metal matrix composites (MMCs) and their unique benefits when used as heat spreaders for GaN devices.
Read More...

MILITARY MICROWAVE DIGEST


MMD March 2014
New Military Microwave Digest

ON THE MARKET


Band Reject Filter Series
Higher frequency band reject (notch) filters are designed to operate over the frequency range of .01 to 28 GHz. These filters are characterized by having the reverse properties of band pass filters and are offered in multiple topologies. Available in compact sizes.
RLC Electronics


SP6T RF Switch
JSW6-33DR+ is a medium power reflective SP6T RF switch, with reflective short on output ports in the off condition. Made using Silicon-on-Insulator process, it has very high IP3, a built-in CMOS driver and negative voltage generator.
Mini-Circuits


Group Delay Equalized Bandpass Filter
Part number 2903 is a group delayed equalized elliptic type bandpass filter that has a typical 1 dB bandwidth of 94 MHz and a typical 60 dB bandwidth of 171 MHz. Insertion loss is <2 dB and group delay variation from 110 to 170 MHz is <3nsec.
KR Electronics


Absorptive Low Pass Filter
Model AF9350 is a UHF, low pass filter that covers the 10 to 500 MHz band and has an average power rating of 400W CW. It incurs a rejection of 45 dB minimum at the 750 to 3000 MHz band, and power rating of 25W CW from 501 to 5000 MHz.
Werlatone


LTE Band 14 Ceramic Duplexer
This high performance LTE ceramic duplexer was designed and built for use in public safety communication and commercial cellular applications. It operates in Band 14 and offers low insertion loss and high isolation to enable clear communications in the LTE network.
Networks International

See all products in this issue


June 2013

Multisim/Ultiboard for Low-Frequency Simulation and Layout
By AWR Corporation

Introduction
RF and microwave circuit designers choose Microwave Office® software because of its complete range of powerful circuit design capabilities, from design capture, to harmonic balance and time-domain simulation, to layout, synthesis, and optimization, and even electromagnetic (EM) analysis and post-layout verification.

The  AWR  Design Environ ent: Microwave Office 10 GHz  LNA  example project.

The Microwave Office design environment is well suited for higher-frequency designs, and, when combined with National Instrument’s Multisim circuit simulation software through AWR Connected™, low-frequency circuit functionalities are added for an even more complete circuit design flow (DC up through microwave/RF). Moreover, NI’s Ultiboard printed circuit board (PCB) layout software is capable of integrating high-frequency circuit layouts with Multisim, enabling designers to rapidly create a layout of a complete prototype, add mechanical and graphical shapes to the design, create 3D views of the final design, and export standard Gerber files, as well as other formats, for fabrication.

With the flexible routing capabilities of Ultiboard, all the particular details of the RF circuit affecting the frequency response are preserved (such as the transmission line bends, matching networks, and ground vias), while all the complementary low-frequency circuits are quickly routed around it.

Figure 1: Preview of the  LNA  layout  in the  Ultiboard DXF  import dialog.

Getting Started in Microwave Office
In the AWR Design Environment™, go to File>Open Example and select the LNA_10GHz.emp project. This project shows the design of a 10GHz low noise amplifier (LNA) built on 10-mil alumina using an NEC 76038 gallium arsenide (GaAs) metal semiconductor field effect transistor (MESFET). Run the analysis and it can be seen that the LNA has 7.7dB gain and 2.15dB NF at 10GHz.

Designing this amplifier in Microwave Office enables users to take advantage of the software’s real-time tuning and frequency subset Smith Chart plots, as well as AWR’s proprietary X-models to account for discontinuities, so that performance can be optimized and validated before committing to fabrication.

Next, let’s take DC biasing into consideration and turn to NI’s Multisim/Ultiboard software.

Figure 2: LNA  layout  after  adding proper ground vias, copper fill, and  ports  in Ultiboard.

Create a Multisim Component for the LNA DXF Export
To create a biasing circuit in Multisim, export the relevant DXF file from the Microwave Office environment by going to Layout>Export and saving the design file as a DXF file on your computer. Remember that the project units were in mils.

Now, go to Ultiboard and open a blank design. Go to Tools>Database>Database Manager and click on Create a New Part, then select New PCB Footprint in the pop-up dialog box.

Figure 1 shows the DXF import dialog. In your new footprint design file, go to File>Import>DXF and import the DXF file that you exported from the Microwave Office software. Make sure you only import the copper layer (merge it with the copper top layer) and ignore the rest of the layers. Remember to set the units to mils.

Select the imported shapes and right-click to go to their properties. Under the copper area tab, make sure you change the fill style to a solid fill style.

Adding Pins
You now need to create 10 pins to connect the LNA to its DC circuitry: one pin each for RF input, RF output, drain bias, and gate bias and six ground pins that connect the through vias to the ground. To add the pins, go to Place>Pins. The LNA layout after adding the vias, copper fill, and ports in Ultiboard is shown in Figure 2.

Adding the LNA to the Ultiboard Database
Once you have finished editing the layout, go to File> Save to Database as and save the new component to the user database. The final layout of the LNA component should look similar to that shown in Figure 3.

Figure 3: Save  the  LNA  component into  the  Ultiboard database for reuse

This LNA design can now be used in Ultiboard, where DC biasing and other low-frequency circuitry can be built around it. At this stage, where distributed high-frequency effects no longer need to be considered in the PCB layout, designers benefit from the easy-to-use PCB prototyping capabilities of Ultiboard.

Conclusion
NI Multisim/Ultiboard and AWR Microwave Office software are complementary and together offer capabilities that enable designers to create circuits spanning from DC to microwave frequencies. Complex tasks such as harmonic balance simulation and SPICE analysis can now be accomplished with a high degree of accuracy, and RF layouts can be readily combined with rapid prototyping tools inclusive of both low and high-frequency circuitry.

To evaluate NI Multisim circuit simulation and Ultiboard PCB layout software, visit www.ni.com/multisim/try

AWR would like to thank Mahmoud Wahby for his contributions to this application note.
Mahmoud Wahby, M.Sc Product Marketing Engineer National Instruments Toronto www.ni.com.

AWR Corporation
www.awrcorp.com
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FROM WHERE WE SIT

Uncertain Times for DefenseIn Defense of DARPA; Lamenting Bell Labs
By Barry Manz

A federal agency like DARPA is a sitting duck for politicians and assorted other critics. It has come up with some truly bizarre programs over years that ultimately either delivered no tangible results, were canceled before they could cause any damage, or attempted to answer questions that nobody was asking or needed answers to. Read More...


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