When implementing RFID access control applications, it can be difficult to know where to start. Since there are multiple RFID frequencies that are used for different applications, it is important to know which frequency range is right for your system. Whether you’re a first time RFID user or looking to update an RFID access control system, the sections below will help determine which frequency is right for your system.
The first thing to consider when choosing a frequency is the overall goal of your system. To get a better idea of how each RFID frequency is used, see the list below:
- LF is typically used to access buildings, rooms, and cabinets.
- HF is often used to access buildings, rooms, and suites.
- UHF is commonly used to access secure parking lots and roadways.
When considering the functionality of your access control system, it is also important to address aspects that can or cannot be compromised. Here are some pros and cons of working with each RFID frequency:
- LF tags do not have secure standards and have slower read rates. However, LF tags work well with applications involving metal and water.
- HF typically does not perform well with applications involving metal and water. However, HF tags have a higher data transfer rate and security standards than LF and are typically available in a small form factor.
- UHF also does not perform well with applications involving metal and water, but it it has the fastest data transfer rate and longest read range of the three options. Some environmental effects can be mitigated by incorporating RF shielding and using specialty tags made for mounting on metal or liquid-filled items.
Understanding the best read range for your system and application is essential in choosing the right frequency. Below is information regarding each passive frequency’s read range:
- LF RFID systems utilize frequencies between 125 – 134 kHz and can usually only be read from near contact to a few centimeters away from the reader.
- HF RFID systems utilize frequencies ranging from 3 – 30 MHz and can typically be read from several inches away from the reader.
- The passive UHF frequency range uses the 860-960 MHz range, with a read range of up to 30 feet (but the typical average is between 5 – 15 feet).
Another thing to consider when implementing an access control system is whether to use an off-the-shelf system or a custom system. Below are descriptions of both types of systems:
Off-the-Shelf: Off-the-Shelf systems are pre-assembled access control systems with a specific use and goal in mind. They have limited customization options and may be more expensive overall than a custom system. In addition to the initial cost of an off-the-shelf system, monthly or yearly payments for software licenses and maintenance are typically required.
Custom: While off-the-shelf systems are premade for a specific use, custom systems allow the user to work with a software developer and create a one-of-a-kind system catered to specific needs. Custom systems can be more cost-effective because of the recurring costs associated with off-the-shelf systems. Additionally, custom systems are more flexible and allow the user to add to or remove functionality and access points depending on the application’s needs.
Cost is an important factor to consider when implementing an RFID access control system. Costs can widely vary depending on each system’s specific requirements and amount of equipment. An access control application with 5 or 6 entry points and will be more expensive than a system with only 1 or 2 entry points. Because tags are a recurring cost, here is the average tag pricing for each frequency that varies depending on the quantity purchased:
- LF tags can range from $2.00 - $10.00 per tag.
- HF tags can range from $0.25 - $5.00 per tag.
- Passive UHF tags can range from $0.15 - $3.00 per tag.
Real-World Application Examples
Below are real-world examples of each of these frequency ranges being used in RFID access control applications:
1. LF- Kitchen Cabinets
Julia Wong, an interior designer, has incorporated RFID into her latest in-home kitchen designs by creating access-controlled drawers and cabinets. Wong designed these cabinets to prevent unauthorized individuals from obtaining potentially harmful objects, like knives and alcohol. (1)
RFID readers can be installed directly inside of cabinets or can be fixed to the outside. Once installed, drawers and cabinets can only open if the LF RFID enabled keycard is tapped to the reader. An auto-relock feature ensures that drawers and cabinets remain secure after use.
2. HF- Hotel Key Cards
The Marriott Maracay Golf Resort in Venezuela is using RFID in guests’ hotel room key cards. By incorporating HF RFID chips into key cards, the hotel can manage access to rooms and in-room safes. Additionally, hotel staff can monitor card use to detect unusual card activity and help recover items potentially left behind in hotel safes. (2)
By placing HF readers on hotel room doors and safes, guests can use their RFID enabled cards to gain access. Door and safe readers are also networked to hotel management’s computers, allowing hotel staff to track misuse of key cards.
3. UHF- Car Parking Lot
Moscow’s International Business Center (MIBC) is using UHF RFID to secure employee parking areas. Due to the high volume of vehicles coming to and from the MIBC, the center sought to install a faster system than their previous HF RFID access control system. With UHF, vehicles do not have to stop in order to be read, making entries and exits more time-efficient to prevent traffic build up. (3)
Each employee is given a key card with a UHF RFID tag inside. The chip inside contains a unique ID number and an encryption key. For vehicles to be approved to enter or exit, key cards must be detected by a reader emitting a matching encryption key. Because UHF RFID typically has a large read range, this encryption provides an added layer of security and lessens the likelihood that a rare case of hacking will occur.
To read more about RFID access control, check out the links below!