It's On the Inside: The Advantages of Embedded Antenna Technology
By David McCartney
Embedded antenna technology is not new or revolutionary. Its development and application has been in use in the defense business for years. What is new is its application to today's wireless handsets, whether they are cellular, PCS, or cordless. It's an application that has, until now, been largely ignored.
The external antenna is the last bastion of technology that is still tied to the 1950s. In the wireless handset business, we have developed and applied a tremendous amount of new technological advances, in digital signal processing (DSP), the reduction of 3 volts, and the man-to-machine-interface (MMI). But even with this wide range of technological advance, wireless handset antenna technology has not been given much attention, or a chance to be developed to its full potential.
It has taken the industry years to move from the whip to the heliax. That is, until now. As consumers today demand a more ergonomic handheld device or robust and reliable wireless handset, several companies are now focused on core antenna technology for the wireless handset market. In addition, a few manufacturers are just beginning to explore and in some cases offer commercially available products with embedded antennas to create a differentiator.
The Right Time is Now
Wireless handsets have made great technological leaps since the first handheld devices of the 1980s were introduced. Who can forget the "bricks" we used to carry? Would you trade in today's shirt pocket devices? What is the phone of the future? Will we continue to compromise on quality in exchange for size?
Technological advancements and competition have brought us to reductions in size and weight while increasing talk and standby time. But today's phone still has one Achilles heal - the antenna.
As with any improvement in design, two major criteria must be met to turn new technology into a commercially acceptable product: performance and cost. The first priority is performance. Does the application of new technology meet or exceed existing technology performance? The second priority is cost: will the incorporation of this new technology reduce product cost?
In today's cellular/PCS handset and cordless handset business, retail prices continue to fall dramatically, driving manufacturers to look to advancements in technology to improve performance and reduce product cost structure and in turn create differentiators for manufacturers' products.
Embedded antenna technology helps create these differentiators. Critical factors in implementing embedded technology into wireless handsets include size, yield, and ease of manufacture.
A look back into our recent past demonstrates how far handset design has come. The form factor of the early 1990s is affectionately referred to as "the brick." Today's micro-handsets have been reduced in size as well as weight. Current advancements in design are working toward an appropriate weight so that the "wearability" of the wireless devices is convenient, functional, and fashionable - fitting easily into a shirt pocket or unobtrusively on a belt.
Until recently, very few companies have been focused on the core technology of embedded antennas for wireless handsets. The need for product differentiation has spurred manufacturers to take a look at companies like RangeStar International, who focuses singularly on attacking the technological challenges of developing embedded antenna solutions with improved size, weight, performance, and reduction of cost when compared to existing exterior antenna products.
Learning from the experience of the defense industry, companies such as RangeStar have applied this background in micro antenna technology to develop new technological breakthroughs in reduced size, increased performance, and dramatic reductions in cost. These developments allow manufacturers to offer embedded technology to compete with the whips and dipoles of today.
Embedded Technology
The development of a new technological approach to solving the requirements of today's wireless handsets drove Rangestar International to look for a convergence to existing technology with a creative new approach.
Patch antennas had been developed and were in use for a number of applications, but due to the performance requirements of today's cellular/PCS handsets, patch antennas alone were not the answer. The lack of performance with patch antenna technology drove RangeStar International to look in two directions: directional technology and omni-directional.
The developing need for improved specific absorption rate (SAR) led RangeStar to initially focus on applying various directional approaches into a new form factor and size. The characteristics of the directional embedded antenna provide inherent improved SAR protection first because of the usual mounting of the antenna on the back of the PCB, thereby creating a shield.
In addition, RangeStar worked with the physics of creating a "C" pattern. In essence, they redirected the energy from the back of the antenna to the front (which is engineering lingo for "Front to Back"). RangeStar patented the "C" planar antenna, which offers tremendous gain of nearly 5 dBi. In lay terms, the "C" planar antenna is a surface mounted embedded antenna that offers tremendous SAR improvement over today's traditional whip or heliax antennas being used in wireless devices. The "C" planar antenna - when used with today's cellular/PCS and cordless handsets - provides access to the hearing impaired. The antenna reduces or eliminates as much as 95% of the distortion caused by today's digital technologies deployed.
Today's directional embedded antennas, such as the "C" planar design, still have some inherent challenges. One of these challenges is the human hand. Handset devices have such small form factors these days that it is easy to cover all or most of the device while talking. This coverage of the device may result in detuning. With the antenna mounted on the back of the PCB, covering the antenna while holding the phone in a user's hand will detune the antenna and thus reduce performance.
Physics is physics, so Rangestar International sought to develop alternate solutions. The first solution is to provide an ergonomic handset design that would force the user to hold the device in a such a way that their hand would not cover the internal antenna. Sounds easy, but actually creating this is and will be harder than it seems for manufacturers and designers.
The second solution was the development of a series of top mounted, perpendicular and horizontal, antennas that would have similar or improved whip performance, weigh less than one gram and cost less than existing whip antennas. Thus, the "T" planar series of antenna was developed. The "T" planar series introduces a revolutionary incorporation of embedded technology and new techniques. It provides an OEM with the flexibility to now retrofit existing product platforms. The T series also enables OEMs to easily incorporate a top mounted antenna that offers whip like performance. Ease of manufacture and reduction of cost are only the early solutions to the hand detuning issue.
Where Embedded Technology Is Headed
With the vision of 3G now coming slowly into focus, the application - if not the basic requirement - for future 3G handsets will call for embedded antennas. The industrial designers working on tomorrow's handset designs are all eliminating the ugly, external antenna of today's handsets as they strive to achieve and deliver futuristic, ergonomic handsets that will serve the next generation. The key is for antenna technology to provide embedded antenna solutions that will deliver the performance that 3G systems will require.
In addition, the drive to multiple frequency applications signals the need for antenna technology to be capable of providing dual-band, triple-band and in some applications even quadruple-band solutions. This will be the challenge for firms such as Rangestar International, and others that are focused on leading-edge antenna technology. How do we get the bandwidth to cover 800 MHz to 1900 MHz or greater? What dialectric can provide this and still be in a small lightweight package? The future will bring us a true world phone, but to achieve the ultimate solution, antenna technology must now keep pace or even exceed the development rate of core technologies.
David McCartney is currently the Vice President, Marketing and Sales for RangeStar Wireless, Inc. McCartney's responsibilities at RangeStar span sales and product development, marketing communications, marketing and distribution strategies for the OEM product line. A wireless industry veteran with more than two decades of experience, McCartney served most recently as Vice President of Marketing and Sales for Bosch Telecom, where he guided the market introduction of the Bosch World 718, the first wireless phone to permit seamless international roaming.