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The working frequency of wireless communication systems will inevitably be developed for the higher‐frequency terahertz (THz) band. An effective way to improve data transmission rates in this band is to adopt higher‐order modulation. However, existing THz wireless communication systems struggle to realise higher‐order modulation and demodulation at high speeds. Baseband digital modulation mixes signals with the same modulation and symbol rate. Different bit streams are sent on the 0.34 THz band and the receiver uses a per‐survivor processing algorithm to separate and demodulate the mixed signal. This doubles the transmission rate of THz data whilst avoiding the problem of modulation and demodulation at high speeds resulting from higher‐order modulation. Both simulation and measured data is used to verify the feasibility of the method. [ABSTRACT FROM AUTHOR]

A tunable multiband folded printed quadrifilar helical antenna (FPQHA) is proposed. Creating slot on the arms of FPQHA is a simple approach for designing multiband helical antenna. Also varying width and length of the slot can cause to tune the interested frequency bands. The operating frequency ranges in L/S/C band that covers L1 GPS band and most of the commercial wireless communication systems, such as WLAN [IEEE 802.11 (2.4/3.6/5 GHz)], LTE and WiMAX (2.5/3.5 GHz). [ABSTRACT FROM AUTHOR]

The average of integer powers of the Gaussian Q‐function over fading distributions is commonly found in the evaluation of the average error performance of wireless communication systems over fading channels. Expressions known in the literature for η–μ and κ–μ fading channels only include solutions for the average of one Gaussian Q‐function and the product of two Gaussian Q‐functions. This limitation has been overcome by providing a general solution for the average of arbitrary powers of the Gaussian Q‐function over η–μ and κ–μ fading channels. [ABSTRACT FROM AUTHOR]

A simpler MIMO transmission method using orthogonal directivities is proposed. In future wireless communication systems, higher data rates will be required since large amounts of data will be transmitted and received. MIMO technology is useful for achieving higher data rates. However, since MIMO detection becomes complicated when the number of antennas becomes large, a simpler method should be considered. To solve this problem, the present authors proposed a spatial division method using orthogonal directivities. This previously proposed method to N streams is expanded transmission for application to much higher data rate systems. Furthermore, using higher order antenna modes at the same frequency to more easily obtain orthogonal directivities is proposed. To evaluate the proposed method, it is confirmed by numerical analysis that the capacity of the proposed method increases without MIMO detection when the number of antennas becomes large. [ABSTRACT FROM AUTHOR]

Multi‐functional antennas are very important in modern wireless communication systems. A novel dual‐band frequency‐reconfigurable antenna with pattern diversity is designed. The antenna consists of a composite right/left‐handed transmission line inspired structure, which works at the zeroth‐order mode (0) around 2.5 GHz and at the first‐order mode (1) around 3.5 GHz. The 0 mode results in an omni‐directional pattern and the 1 mode results in a broadside pattern. By adding varactors to continuously reconfigure the structure, the antenna is able to tune its lower resonant frequency from 2.36 to 2.60 GHz, which fully covers the 2.4–2.5 GHz ISM band, and tune its higher resonant frequency from 3.34 to 3.73 GHz, which fully covers the 3.4–3.7 GHz WiMAX band. Simulations and experiments match well, proving the validity of this new concept. [ABSTRACT FROM AUTHOR]

A new bound on the frequency hopping (FH) sequence set with respect to the size of the frequency slot set q, the sequence length N, the family size M, the maximum periodic Hamming correlation Hm is established. The new bound is tighter than the Singleton bound on the FH sequence set when gcd (Hm + 1, N) ≠ 1. [ABSTRACT FROM AUTHOR]

A new balun–bandpass filter with a quasi‐elliptic response for 60 GHz wireless communication systems is proposed. It is designed in the form of a substrate integrated waveguide (SIW) and fabricated with the standard low‐temperature co‐fired ceramic (LTCC) technology. Both simulated and experimental results are provided, which have good agreement. The results indicate that the proposed balun filter has a good balance performance with <1.1 dB amplitude imbalance and better than 3.4° phase imbalance, compact size, as well as high selectivity. [ABSTRACT FROM AUTHOR]

New analytical closed‐form expressions are derived for the probability density function and the cumulative distribution function of the squared Rician shadowed variates. In particular, the application of such results in the performance analysis of wireless communication systems is investigated. [ABSTRACT FROM AUTHOR]

A broadband gain enhancement endfire antenna is presented. The gain enhancement is achieved by loading with an I‐shaped resonator (ISR) structure in the endfire direction. Broad bandwidth is realised by using a microstrip‐to‐coplanar balun and bowtie dipole elements, while gain enhancement is achieved by loading the ISR structure in the endfire direction. The measurements show that the ISR‐loaded antenna presents a gain of about 4–8 dB in the whole working band (4.5–9.5 GHz), which is about 2 dB more than the unloaded one. The advantages of broad bandwidth and high gain make this antenna valuable in wireless communication systems. [ABSTRACT FROM AUTHOR]