The ability of tag, identify and track objects in real time has always been the holy grail for military strategists and generals. On the battlefields the generals need to know exactly where his resources are and how fast they can be deployed to specific areas of a battle zone.  In the old days, generals would perch themselves on a high ground to get a good view and issue orders accordingly. This “manual way” of doing things has been around for thousands of years. 

The automated form tagging and tracking did not become a reality until some 60 years ago. During the early phases of World War II, superior German forces overran mainland Europe in the early months of 1940, invading neighbouring Poland, France, Belgium and Holland. With Western Europe securely at hand, Hitler then set his sight on the island across the English Channel. In what was the largest and most sustained bombing campaign attempted at that time, the Luftwaffe, as the German air force was known, conducted relentless day and night bombing of all major cities in Great Britain. Out numbered two to one, the Royal Air Force (RAF) is faced with the daunting task of defending the island nation from these constant air raids and an imminent invasion.

Unlike its enemies, the RAF had limited fuel supplies and resources; it simply could not afford to scramble their fighter planes every time blips appear on their radar screens. The British needed a way to distinguish their own aircraft appearing on their radar screens from that of their enemies’. 

So the RAF came up with the IFF or Identification Friend or Foe system. The IFF involves tagging the friendly aircrafts with transponders that responds to high frequency signals sent to it by ground bases. Incoming aircrafts that do not respond to the signal are considered hostile and will be intercepted.  Although not perfect, the system helped save precious fuel and help in the deployment of fighter aircrafts where they are most needed. As history would have it, the RAF defeated the Luftwaffe by inflicting heavy losses despite having limited resources. Though not the only factor, the IFF provided a means for the RAF to tag and track its fighters, giving the RAF a significant tactical advantage.

Since World War II, scientists in United States, Europe and Japan further experimented with radio frequency energy as a means of remotely identifying objects. It wasn’t until 1973 when the first US patent was awarded to Mario W. Cardullo for an active Radio Frequency Identification or RFID tag with rewritable memory. At the time the RFID technology were very costly and mostly used to track larger, high cost items like cattle and highly secured materials such as nuclear fuel.

The RFID tags or transponders are interesting devices; size wise they can be as small as a grain of sand or can be as big as cigarette box. These modern RFID tags consist on a memory chip that is able to store up to 2 kilobytes of data and an antenna.  The amazing thing about it is that it is able to transmit its contents via a radio wave even without battery power. The secret is that the tag draws its energy from an electromagnetic field generated by the tag reader, which can be positioned up to several meters away. A small electric current is generated by waving the tag in the electromagnetic field, which then powers the tag to transmit its memory contents to the reader. 

For most of us RFID may seemed like a leading edge technology, in fact it is being used in our daily lives. Car security and alarm systems is a good example – RFID tags embedded in the car keys report its serial number to the car and validated before the engine is allowed to start. Employee identification tags open the doors when it is waved in front of the card reader.  In fact our ubiquitous Touch ‘n Go cards runs on RFID technology. Operated by Rangkaian Segar Sdn. Bhd., the Touch ‘n Go card has a unique ID number and stores the purchased value on an RFID tag.

The card contents are updated every time the users waves the card at the reader at entrances to tolls and subway stations, the purchased value is deducted from the card when the user touches the card again at the exit. Each card has a life expectancy of 64,000 read/write cycles, which translates to about 10 years. Touch ‘n Go has been around since March 1997, today there are some 4.4 million users averaging more than 1 million transactions per day.

Touch n’ Go is said to be 3 times faster that cash payments because there is no need to cashiers to return the change to the commuter, the exact amount for the fare is automatically deducted from the card.  Perhaps the only limitation of the Touch ‘n Go card is its reading range; which is only about 10 cm. These are known as “passive tags”, meaning they rely on the reader for its power and they operate at the low range of radio frequency.

There are in fact 4 different frequency ranges that RFID tags operate in – low, high, ultra high and microwave frequencies. The higher the frequency, the greater the reading range, on the high end, the microwave tags will get you up to 10 meters.  The downside however is that these long range “active tags” needs to be powered by a battery, therefore significantly increasing its size. Cost wise, the passive tags are the cheapest to manufacture and deploy, hence its popularity.  

The SmartTag installed in our cars are RFID transponders that extent the range of the Touch ‘n Go cards. Powered by a 9 volt internal battery, it reads the Touch n’ Go card when triggered at the toll gate and transmits its contents to the reader overhead. The toll amount is deducted from the card value and then transmitted back to the card. With it, cars can drive thru the toll gates without drivers having to wind down the window to tap the readers.

The speed and efficiency in processing large numbers of commuters and road traffic makes RFID the ideal choice for toll and fare payments. Many countries have implemented such payment systems in their toll ways and public transport systems, including Hong Kong, Norway, Korea, Taiwan, Brazil, Singapore and Pakistan.

Next … RFID everywhere.


Article by: Gilbert Chang