• Book Name: Millimeter Wave Technology in Wireless Pan, Lan, and Man edited by Shao-Qiu Xiao
• Author: Shao-Qiu Xiao
• Pages: 448
• Size: 5 MB

Millimeter Wave Technology in Wireless Pan Lan and Man

The increase in high-performance personal computers (PCs) and multimedia equipment in offices and homes requires high-speed and broadband wireless data transmission. This requirement makes wireless indoor communication systems such as wireless local area networks (WLAN) and personal area networks (PAN) because of their portable convenience. For such short-range indoor broadband WLAN and PAN systems, the millimeterwave band offers significant advantages in supplying enough bandwidth for the transmission of various multimedia content. In particular, there has been an increasing requirement for the development of the V-band WLAN for commercial applications. The frequency of 60 GHz is very useful for short-distance wireless communications due to the strong absorption characteristic by oxygen in the atmosphere. Therefore, frequency efficiency is improved compared to other frequency bands.

In the last few decades, many research groups in the world have developed millimeter-wave LAN systems. For example, Communications Research Laboratory (CRL, now NiCT) took up the project of developing indoor WLAN systems using millimeter waves in 1992 [1]. The final goal of the millimeter-wave WLAN systems is to provide point-to-multipoint access with transmission rates higher than 100 Mbps for the connectivity of broadband integrated services digital networks (B-ISDNs) or conventional fast Ethernet. For these millimeter-wave WLAN applications, we have to solve some problems. First of all, we have to reduce the size and cost of the systems.

Millimeter Wave Technology in Wireless Pan Lan and Man

The millimeterwave systems are generally fabricated using HIC (hybrid integrated circuit) technology, causing a large system. MMIC (monolithic millimeter-wave integrated circuit) technology is regarded as an alternative to HIC technology due to its ability to integrate active with passive elements on a single semiconductor substrate [2–6]. The MMIC has advantages, such as small size, high reliability, high productivity, and low cost due to using semiconductor technologies compared to the conventional HIC. The main objective of this chapter is to discuss the MMIC technology and its applications for millimeter-wave wireless LAN. First, millimeter-wave WLAN will be introduced. Then, the modeling of active and passive devices will be described. The design and fabrication technologies of millimeter-wave circuits are presented. Finally, millimeter-wave monolithic circuits for WLAN applications are explained.

1.2 Millimeter-Wave Wireless Local Area Network

Recently, a broadband and high-speed indoor network for office and home environments has been required. Additionally, microwave frequency bands have been saturated and there is growing necessity to exploit new frequency bands that have not yet been utilized for commercial applications. For this reason, utilization of the millimeter-wave band has been recommended, and much research has been devoted to developing millimeterwave wireless LAN. Advantages of millimeter-wave communication are very wide frequency band, high-speed transmission, and radiated power limitation for unlicensed use. Therefore, millimeter-wave WLAN can be utilized in short-range communication and indoor networks. In particular, a 60-GHz band is very useful for wireless short-distance communications due to strong absorption by oxygen. Thus, compared to other frequency bands, frequency efficiency is improved.  . Features to be noted are:

1. Good coexistence between millimeter-wave system and 802.11a/b/g & Bluetooth due to large frequency difference

2. Higher speed transmission, more than 1 Gbps

3. Exploitation of antenna directivity

4. Simple modulation/demodulation 5. Simple signal processing

Millimeter-wave WLAN is possible for wireless networks such as multimedia equipment, home appliances, videosignal transmissions, and personal computers. Utilization of millimeter-wave WLAN is explained in Figure 1.2. A millimeter-wave circuit and system have been developed using a waveguide module, hybrid integrated circuit method, resulting in large size, high cost, and low productivity. Use of these systems in wireless LAN has many problems due to small size and low cost in wireless LAN. To overcome these problems, high-speed devices such as high electron mobility transistors (HEMTs) and MMTCs need to be added to the millimeterwave wireless LAN. Figure 1.3 shows normal millimeter-wave WLAN and millimeter-wave circuit components.

Millimeter-wave components are usually composed of a low-noise amplifier (LNA), a power amplifier, an oscillator, and an up/down mixer. Also, passive components such as a filter, an antenna, a coupler, and a circulator are required. These components can be varied with system architecture. Millimeter-wave circuits must be realized high-speed operating characteristics, high linearity, small size, and low cost. For this reason, many technologies such as device modeling, circuit design, circuit fabrication, and measurement technology need to be developed for MMICs.

Millimeter wave technology in wireless pan lan and man.