**2. Prospects of forward directional antennas for handheld RFID readers**

Also when the operating frequency of RFID systems rises to the microwave region (2.45/5.8 GHz bands), the reader antenna design becomes more delicate and critical. This is especially true when a directional antenna is needed for handheld applications. However, it is a popu‐ lar practice for handheld RFID readers to assemble a vertically radiating directional antenna in right angle with the reader; thus the radiation literally becomes front-directional to the reader (Fig. 1). This arrangement significantly increases the actual RFID reader profile. Hence it is greatly advantageous for a compact RFID reader to produce antennas with front-

Advancements and Prospects of Forward Directional Antennas for Compact Handheld RFID Readers

http://dx.doi.org/10.5772/53283

153

(a) (b)

**Figure 1.** Handheld RFID reader with an external antenna module (a) (Ukkonen et al. 2007), (b) (MC3190-Z Handheld

**3. Evolution of forward directional antennas & limitations: A literature**

In this section we will focus on the development of multi-band antenna designing process. In last few years, there are a lot of antennas multi-band antennas has been designed, but most of them are omni-directional in radiation manner. But still some novel structures can be found in recent researches, that provide multi-band operation with directional radiation characteristics (Li et al. 2012, Mobashsher et al. 2010, Sabran et al. 2011). However, all of these antennas use a big metallic ground plane in order to reflect the radiation from the patch. Hence the actual applied antenna profile is bigger than the patch alone. So these an‐ tennas are not suitable for portable RFID applications. Another technique is widely applied in antenna domain in order to achieve directional radiation patters- the utilization of surface

In literature, surface-wave or end-fire antennas are mostly used to produce front-directional radiation patterns. Folded dipole (Fan et al. 2009) and folded (Yang et al. 2010) antennas are

directional radiation patterns.

RFID Reader 2012).

**scenario**

waves (also called trapper waves) (Zucker 1993).

Radio frequency identification (RFID) technology having a huge potential with higher pro‐ duction efficiency, real-time inventory updates, greater product security and restricting counterfeit products, is becoming rapidly engaged in production, transportation, and retail‐ ing of products. On the investment front, more than 40% of shippers have increased their investment in RFID technology for supply chain applications (Research and Markets 2012). RFID technology is rapidly evolving due to (Cole P. H. 2003):


The global RFID market is projected to reach US\$18.7 billion by the year 2017 where growth will be primarily driven by fast paced deployments of RFID projects in developing Asian countries, especially in China. Developments in the field of smart labels are projected to hold the key to future revenue growth (Research and Markets 2012). However, RFID is now at a stage where there are potentially large benefits from wider application but still some barriers remain.

It is widely known that handheld RFID readers need more compactness in design than fixed or mounted readers. Thus it is more challenging to make the designs more compact to meet the expectations of the users. Similar to mobile communications, the multi-standard capabil‐ ity, high data performance and compact profile are becoming obvious expectations of the users of RFID devices. Among the frequency bands that have been assigned to RFID appli‐ cations, higher-frequencies have the advantage of high data transfer rate with far field detec‐ tion capability (Islam et al. 2010).

Directional antennas usually radiates in a directive manner. They force the electromagnetic energy into a specific and desired direction. This type of antenna decreases the interferences of other tags in the undesired direction, while also increasing the reading range as well, since the gain of the directional antennas are higher than the omni-directional antennas.

In order to reduce the overall size of the handheld RFID readers, the need to reduce the size of the antenna is highly essential. But reducing the size of antenna limits its performances. Also when the operating frequency of RFID systems rises to the microwave region (2.45/5.8 GHz bands), the reader antenna design becomes more delicate and critical. This is especially true when a directional antenna is needed for handheld applications. However, it is a popu‐ lar practice for handheld RFID readers to assemble a vertically radiating directional antenna in right angle with the reader; thus the radiation literally becomes front-directional to the reader (Fig. 1). This arrangement significantly increases the actual RFID reader profile. Hence it is greatly advantageous for a compact RFID reader to produce antennas with frontdirectional radiation patterns.

**2. Prospects of forward directional antennas for handheld RFID readers**

Radio frequency identification (RFID) technology having a huge potential with higher pro‐ duction efficiency, real-time inventory updates, greater product security and restricting counterfeit products, is becoming rapidly engaged in production, transportation, and retail‐ ing of products. On the investment front, more than 40% of shippers have increased their investment in RFID technology for supply chain applications (Research and Markets 2012).

**•** realization in the business community of the benefits of widespread adoption in the sup‐

**•** adoption by designers of sensible concepts in the arrangement of data between labels and

**•** development of efficient data-handling methodologies in the relevant supporting com‐

**•** development of new manufacturing techniques that will achieve manufacture of billions

The global RFID market is projected to reach US\$18.7 billion by the year 2017 where growth will be primarily driven by fast paced deployments of RFID projects in developing Asian countries, especially in China. Developments in the field of smart labels are projected to hold the key to future revenue growth (Research and Markets 2012). However, RFID is now at a stage where there are potentially large benefits from wider application but still some

It is widely known that handheld RFID readers need more compactness in design than fixed or mounted readers. Thus it is more challenging to make the designs more compact to meet the expectations of the users. Similar to mobile communications, the multi-standard capabil‐ ity, high data performance and compact profile are becoming obvious expectations of the users of RFID devices. Among the frequency bands that have been assigned to RFID appli‐ cations, higher-frequencies have the advantage of high data transfer rate with far field detec‐

Directional antennas usually radiates in a directive manner. They force the electromagnetic energy into a specific and desired direction. This type of antenna decreases the interferences of other tags in the undesired direction, while also increasing the reading range as well, since the gain of the directional antennas are higher than the omni-directional antennas.

In order to reduce the overall size of the handheld RFID readers, the need to reduce the size of the antenna is highly essential. But reducing the size of antenna limits its performances.

RFID technology is rapidly evolving due to (Cole P. H. 2003):

**•** development of improved techniques for multiple tag reading;

**•** increased awareness of the technology;

152 Radio Frequency Identification from System to Applications

**•** appreciation of the need for cost reduction, and

ply chain;

databases;

barriers remain.

munication networks;

of labels at acceptable costs.

tion capability (Islam et al. 2010).

**Figure 1.** Handheld RFID reader with an external antenna module (a) (Ukkonen et al. 2007), (b) (MC3190-Z Handheld RFID Reader 2012).
