The Opportunities and Challenges of LTE Unlicensed in 5 GHz
David Witkowski, Executive Director, Wireless Communications Initiative
In 1998, the Federal Communications Commission established the Unlicensed National Information Infrastructure or U-NII 5 GHz bands. These are used primarily for Wi-Fi networks in homes, offices, hotels, airports, and other public spaces and also consumer devices. U-NII is also used by wireless Internet Service Providers, linking public safety radio sites, and for monitoring and critical infrastructure such as gas/oil pipelines.

MMD March 2014

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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.

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.

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

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May 2014

RF Power Amplifier Delivers 2 W and 40 dB Gain From 1500 to 2700 MHz
By Mario Bokatius, Freescale Semiconductor, Inc.

Whether the application is a macro cell or a small cell the ability of an RF power amplifier to provide broad versatility is a highly valuable attribute. For example, if the amplifier can deliver high performance over a wide array of frequency bands used by wireless carriers and can be optimized for each one, it can cost-effectively serve multiple applications within an OEM’s portfolio. This not only allows wide range of products to be created with a minimum of designs but reduces the bill of materials. Freescale Semiconductor has introduced a low-cost InGaP GaAs HBT RF power amplifier housed in a 4x4-pin QFN surface-mount package that is the first such device to deliver 2-W (+33-dBm) and more than 40 dB of gain from 1500 to 2700 MHz.

Figure 1: Freescale‘s MMZ25333B three-stage RF power

Freescale's MMZ25333B three-stage RF power amplifier (Figure 1) can be used in a variety of ways, as either a driver or predriver in a macro cell or micro cell base station, or as the final amplifier in a small cell or repeater, for example. It supports any wireless standard and is powered from a single 5-VDC supply. Matching networks on the PC board can be adjusted to optimize the performance of the MMZ25333B at any band within its frequency range. In addition, quiescent bias current is adjustable to provide an optimum combination of linearity and efficiency to meet the requirements of a specific application. It has an integrated single-ended power detector as well.

Virtually all wireless systems today employ a Doherty amplifier architecture in the final amplification stage and are linearized using digital predistortion (DPD) or analog pre-distortion (APD) circuits. The MMZ25333B is well suited for use as a predriver or driver in a Doherty amplifier, and it can be located either on the power amplifier board or on the transceiver board, depending on the design. The device has very high gain, in excess of 40 dB, which can eliminate the need for additional gain stages, reducing the cost and complexity of the circuit.

Fiugre 2: A typical Doherty amplifier employed in a macro or micro cell in which the MMZ25333B acts as a driver amplifier.

The Doherty amplifier lineup shown in Figure 2 is typical of a linearized macro or micro cell base station power amplifier. The MMZ25333B acts as the driver amplifier, after which its output is split between the main and peaking amplifiers. In Figure 3, the device is used as a predriver and its output is split between two drivers, which then feed the main and peaking amplifiers. When used as the final-stage amplifier in a non-linearized small cell, the quiescent bias current to the device can be increased to improve its linearity. These are only two of many configurations in which the MMZ25333B can be used.

Figure 3: In this configuration the MMZ25333B is used as a predriver feeding two driver amplifiers.

The MMZ25333B’s combination of very high gain, broad bandwidth, and the ability to be optimized for both the type of amplifier in which it is used and its operating frequency make it highly appealing in a broad array of applications. It is in production and reference designs and other information are available. More information can be obtained at

Freescale Semiconductor, Inc.
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Uncertain Times for DefenseOpen’s Systems and Changes in DoD Procurement: This Time It’s Real
By Barry Manz

The U.S. Department of Defense has a well-earned reputation for inertia. Many proposals for change are made – but nothing happens. The COTS initiative, which promised cost savings through the use of off-the-shelf commercial parts, sounded terrific at the time. It heralded a major departure from standard DoD procurement that more or less guaranteed that every system would be different in part because it used parts that were developed from scratch, leading to “one-off” systems that were very expensive. Read More...

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