Claims:1. A radio communication device comprising: a plurality of antenna arrays each configured to generate a steerable antenna beam according to a respective beamforming codeword, wherein each of the plurality of antenna arrays is configured to obtain the respective beamforming codeword from a single-antenna-array steering codebook that is reused by each of the plurality of antenna arrays; and a beamforming circuit configured to weight signals for the plurality of antenna arrays to coordinate the steerable antenna beams from a subset of the plurality of antenna arrays to form a combined antenna beam in a first steering direction. 2. The radio communication device of claim 1, wherein the respective beamforming codewords each comprise a plurality of complex valued beamforming weights, and wherein the plurality of antenna arrays are each configured to generate the respective steerable antenna beam by applying the plurality of complex beamforming weights of the respective beamforming codeword to a plurality of weighting circuits of each antenna array. 3. The radio communication device of claim 2, wherein the plurality of weighting circuits are a plurality of radio frequency (RF) beamforming circuits. 4. The radio communication device of claim 1, wherein each beamforming codeword of the single-antenna-array steering codebook is designed to provide antenna array steering in a predefined steering direction. 5. The radio communication device of claim 1, wherein each beamforming codeword of the single-antenna-array chain steering codebook corresponds to a linear progressive phase shifted codeword. 6. The radio communication device of claim 1, wherein the beamforming circuit is configured to weight the signals for the plurality of antenna arrays to coordinate the steerable antenna beams from the subset of the plurality of antenna arrays to form the combined antenna beam in the first steering direction by: applying a phase shift to each of the signals for each of the subset of the plurality of antenna arrays to create a predefined phase separation between each of the signals. 7. The radio communication device of claim 1, wherein the beamforming circuit is configured to change the weighting of the signals for the plurality of antenna arrays to generate different combined antenna beams from the steerable antenna beams of different subsets of the plurality of antenna arrays, wherein each of the plurality of antenna arrays of the different subsets of the plurality of antenna arrays are configured to reuse the single-antenna-array steering codebook to generate the steerable antenna beams that form the different combined antenna beams. 8. The radio communication device of claim 1, wherein the beamforming circuit is configured to adjust the weighting of the signals for the plurality of antenna arrays to coordinate the steerable antenna beams from a second subset of the plurality of antenna arrays to form a second combined antenna beam in a second steering direction. 9. The radio communication device of claim 8, wherein the second subset of the plurality of antenna arrays is a different size than the subset of the plurality of antenna arrays and wherein the subset of the plurality of antenna arrays. 10. The radio communication device of claim 8, wherein the second subset of the plurality of antenna arrays are configured to utilize the single-antenna-array steering codebook to form the first combined antenna beam and the second combined antenna beam. 11. The radio communication device of claim 1, wherein the beamforming circuit is configured to adjust the weighting of the signals for the plurality of antenna arrays to steer the steerable antenna beams from the plurality of antenna arrays in a plurality of different steering directions. 12. The radio communication device of claim 1, wherein the plurality of antenna arrays are configured to transmit wireless signals via the steerable antenna beams or receive wireless signals via the steerable antenna beams. 13. A radio communication device comprising: a plurality of antenna arrays each comprising a plurality of intermediate frequency (IF) beamforming circuits and a plurality of radio frequency (RF) beamforming circuits, wherein the plurality of RF beamforming circuits are configured to steer an antenna beam for the corresponding antenna array according to a respective steering codeword and the plurality of IF beamforming circuits are configured to performing beam broadening on the antenna beam for the corresponding antenna array according to a respective broadening codeword; and a digital beamforming circuit configured to weight signals for the plurality of antenna arrays to coordinate the steerable antenna beams from a subset of the plurality of antenna arrays to form a combined antenna beam in a first steering direction. 14. The radio communication device of claim 13, wherein the respective steering codeword for the plurality of RF beamforming circuits of each of the plurality of antenna arrays is selected from a single-antenna-array steering codebook that is reused by each of the plurality of antenna arrays. 15. The radio communication device of claim 13, wherein each of the respective broadening codewords specifies a phase distribution for application by the plurality of IF beamforming circuits. 16. The radio communication device of claim 13, wherein each of the plurality of IF beamforming circuits of a given antenna array of the plurality of antenna arrays is connected to a subset of the plurality of RF beamforming circuits of the antenna array, and wherein each of the plurality of IF beamforming circuits is configured to apply a signal weighting to signals for the respective subset of the plurality of RF beamforming circuits. 17. The radio communication device of claim 13, wherein each respective steering codeword is designed to provide antenna array steering in a predefined steering direction. 18. A radio communication device comprising: a plurality of antenna arrays each configured to generate a steerable antenna beam according to a respective beamforming codeword, wherein each of the plurality of antenna arrays is configured to obtain the respective beamforming codeword from a single-antenna-array steering codebook that is common to each of the plurality of antenna arrays; and a beamforming circuit configured to weight signals for the plurality of antenna arrays to coordinate the steerable antenna beams from a subset of the plurality of antenna arrays independently of the respective beamforming codewords assigned to the plurality of antenna arrays to form a combined antenna beam in a first steering direction. 19. The radio communication device of claim 18, wherein the respective beamforming codewords each comprise a plurality of complex valued beamforming weights, and wherein the plurality of antenna arrays are each configured to generate the respective steerable antenna beam by applying the plurality of complex beamforming weights of the respective beamforming codeword to a plurality of weighting circuits. 20. The radio communication device of claim 19, wherein the plurality of weighting circuits are a plurality of RF beamforming circuits. 21. The radio communication device of claim 18, wherein each beamforming codeword of the single-antenna-array steering codebook is designed to provide antenna array steering in a predefined steering direction. 22. The radio communication device of claim 18, wherein each beamforming codeword of the single-antenna-array steering codebook corresponds to a linear progressive phase shifted codeword. 23. The radio communication device of claim 18, wherein the beamforming circuit is configured to weight the signals for the plurality of antenna arrays to coordinate the steerable antenna beams from the subset of the plurality of antenna arrays to form the combined antenna beam in the first steering direction by: applying a phase shift to each of the signals for each of the subset of the plurality of antenna arrays to create a predefined phase separation between each of the signals. 24. The radio communication device of claim 18, wherein the subset of the plurality of antenna arrays with coordinated beams that generate the combined antenna beam is adjustable and each reuse the single-antenna-array steering codebook to generate the combined antenna beam. 25. The radio communication device of claim 18, wherein the beamforming circuit is configured to change the weighting of the signals for the plurality of antenna arrays to generate different combined antenna beams from the steerable antenna beams of different subsets of the plurality of antenna arrays, wherein each of the plurality of antenna arrays of the different subsets of the plurality of antenna arrays are configured to reuse the single-antenna-array steering codebook to generate the steerable antenna beams that form the different combined antenna beams. Dated this 10th Day of May 2017 (P. Dileep Kumar) Registration Number: IN/PA-1364 For Law Firm of Naren Thappeta Agent for Applicant , Description:FORM 2 THE PATENTS ACT, 1970 (39 of 1970) COMPLETE SPECIFICATION (See section 10; rule 13) 1. TITLE OF THE INVENTION: MODULAR ANTENNA ARRAY BEAMFORMING 2. APPLICANT: (a). 2 INTEL CORPORATION (c). 2 2200 Mission College Boulevard Santa Clara, California 95054 (US) 3. Nationality (b). 3 USA THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE NATURE OF THIS INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED Technical Field Various embodiments relate generally to steering of modular antenna arrays. Background Antenna-based communication systems may utilize beamforming in order to create steered antenna beams with an antenna array. Beamforming systems may adjust the delay and/or gain of each of the signals transmitted by (or received with in the receive direction) the elements of an antenna array in order to create patterns of constructive and destructive inference at certain angular directions. Through precise selection of the delays and gains of each antenna element, a beamforming architecture may control the resulting interference pattern in order to realize a steerable “main lobe” that provides high beamgain in a particular direction. Many beamforming systems may allow for adaptive control of the beam pattern through dynamic adjustment of the delay and gain parameters for each antenna element, and accordingly may allow a beamformer to constantly adjust the steering direction of the beam such as in order to track movement of a transmitter or receiver of interest. Beamforming architectures may conventionally employ one or both of digital and radio frequency (RF) processing in order to apply the desired delay and gain factors at each element of the array. Phased antenna arrays are a particularly favored RF beamforming technique for narrowband signals which relies on the approximate equivalence between phase shifts and time delays for narrowband signals. Accordingly, phased antenna arrays may place an RF phase shifter in the signal path of each antenna element and allow the individual phase shift values to be adjusted in order to steer the resulting antenna beam. Although many phased array designs achieve sufficient performance with phase-only control, variable gain amplifiers and other techniques such as tapering may additionally be implemented in order to also allow for gain adjustment. In contrast to the analog RF processing of RF beamformers, digital beamformers may employ digital processing in the baseband domain in order to impart the desired phase/delay and gain factors on the antenna array. Accordingly, in digital beamforming systems, the phase and gain for each antenna element may be applied digitally to each respective antenna signal in the baseband domain as a complex weight. The resulting weighted signals may then each be applied to a separate radio frequency (RF) chain, which may each mix the received weighted signals to radio frequencies and provide the modulated signals to a respective antenna element of the antenna array. As each antenna element in a digital beamforming system requires an exclusive RF chain, many digital beamforming solutions may require a substantial amount of hardware and thus have considerable cost and power-consumption rates. Hybrid beamforming solutions may apply beamforming in both the baseband and RF domains, and may tilize a reduced number of RF chains connected to a number of low-complexity analog RF phase shifters. Each analog RF phase shifter may feed into a respective antenna element of the array, thus creating groups of antenna elements that each correspond to a unique RF phase shifter and collectively correspond to a common RF chain. Such hybrid systems may thus reduce the number of required RF chains by accepting slight performance degradations resulting from the reliance on RF phase shifters instead of digital complex weighting elements. Brief Description of the Drawings In the drawings, like reference characters generally refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the invention are described with reference to the following drawings, in which: FIG. 1 shows an RF beamforming architecture; FIG. 2 shows a hybrid digital/RF beamforming architecture; FIG. 3 shows an illustration of beamsteering for an antenna array; FIG. 4 shows a first modular beamforming architecture; FIG. 5 shows a second modular beamforming architecture; FIG. 6 shows a first exemplary operation mode of modular beamforming; FIG. 7 shows a second exemplary operation mode of modular beamforming; FIG. 8 shows a third exemplary operation mode of modular beamforming; FIG. 9 shows a fourth exemplary operation mode of modular beamforming; FIG. 10 shows a table detailing a first beam broadening technique; FIG. 11 shows a chart detailing a second beam broadening technique; and FIG. 12 shows a method of operating a radio communication device. Description The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and embodiments in which the invention may be practiced. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration”. Any embodiment or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or designs. The words “plural” and “multiple” in the description and the claims expressly refer to a quantity greater than one. Accordingly, any phrases explicitly invoking the aforementioned words (e.g. “a plurality of [objects]”, “multiple [objects]”) referring to a quantity of objects expressly refers more than one of the said objects. The terms “group (of)”, “set [of]”, “collection (of)”, “series (of)”, “sequence (of)”, “grouping (of)”, etc., and the like in the description and in the claims, if any, refer to a quantity equal to or greater than one, i.e. one or more. The terms “proper subset”, “reduced subset”, and “lesser subset” refer to a subset of a set that is not equal to the set, i.e. a subset of a set that contains less elements than the set. It is appreciated that any vector and/or matrix notation utilized herein is exemplary in nature and is employed solely for purposes of explanation. Accordingly, it is understood that the approaches detailed in this disclosure are not limited to being implemented solely using vectors and/or matrices, and that the associated processes and computations may be equivalently performed with respect to sets, sequences, groups, etc., of data, observations, information, signals, samples, symbols, elements, etc. Furthermore, it is appreciated that references to a “vector” may refer to a vector of any size or orientation, e.g. including a 1x1 vector (e.g. a scalar), a 1xM vector (e.g. a row vector), and an Mx1 vector (e.g. a column vector). Similarly, it is appreciated that references to a “matrix” may refer to matrix of any size or orientation, e.g. including a 1x1 matrix (e.g. a scalar), a 1xM matrix (e.g. a row vector), and an Mx1 matrix (e.g. a column vector). A “circuit” as used herein is understood as any kind of logic-implementing entity, which may include special-purpose hardware or a processor executing software. A circuit may thus be an analog circuit, digital circuit, mixed-signal circuit, logic circuit, processor, microprocessor, Central Processing Unit (CPU), Graphics Processing Unit (GPU), Digital Signal Processor (DSP), Field Programmable Gate Array (FPGA), integrated circuit, Application Specific Integrated Circuit (ASIC), etc., or any combination thereof. Any other kind of implementation of the respective functions which will be described below in further detail may also be understood as a “circuit”. It is understood that any two (or more) of the circuits detailed herein may be realized as a single circuit with substantially equivalent functionality, and conversely that any single circuit detailed herein may be realized as two (or more) separate circuits with substantially equivalent functionality. Additionally, references to a “circuit” may refer to two or more circuits that collectively form a single circuit. The term “circuit arrangement” may refer to a single circuit, a collection of circuits, and/or an electronic device composed of one or more circuits. As used herein, “memory” may be understood as a non-transitory computer-readable medium in which data or information can be stored for retrieval. References to “memory” included herein may thus be understood as referring to volatile or non-volatile memory, including random access memory (RAM), read-only memory (ROM), flash memory, solid-state storage, magnetic tape, hard disk drive, optical drive, etc., or any combination thereof. Furthermore, it is appreciated that registers, shift registers, processor registers, data buffers, etc., are also embraced herein by the term memory. It is appreciated that a single component referred to as “memory” or “a memory” may be composed of more than one different type of memory, and thus may refer to a collective component comprising one or more types of memory. It is readily understood that any single memory component may be separated into multiple collectively equivalent memory components, and vice versa. Furthermore, while memory may be depicted as separate from one or more other components (such as in the drawings), it is understood that memory may be integrated within another component, such as on a common integrated chip. The term “base station” used in reference to an access point of a mobile communication network may be understood as a macro base station, micro base station, Node B, evolved NodeB (eNB), Home eNodeB, Remote Radio Head (RRH), relay point, etc. As used herein, a “cell” in the context of telecommunications may be understood as a sector served by a base station. Accordingly, a cell may be a set of geographically co-located antennas that correspond to a particular sectorization of a base station. A base station may thus serve one or more cells (or sectors), where each cell is characterized by a distinct communication channel. Furthermore, the term “cell” may be utilized to refer to any of a macrocell, microcell, femtocell, picocell, etc. For purposes of this disclosure, radio communication technologies may be classified as one of a Short Range radio communication technology, Metropolitan Area System radio communication technology, or Cellular Wide Area radio communication technology. Short Range radio communication technologies include Bluetooth, WLAN (e.g. according to any IEEE 802.11 standard), and other similar radio communication technologies. Metropolitan Area System radio communication technologies include Worldwide Interoperability for Microwave Access (WiMax) (e.g. according to an IEEE 802.16 radio communication standard, e.g. WiMax fixed or WiMax mobile) and other similar radio communication technologies. Cellular Wide Area radio communication technologies include Global System for Mobile Communications (GSM), Code Division Multiple Access 2000 (CDMA2000), Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE), General Packet Radio Service (GPRS), Evolution-Data Optimized (EV-DO), Enhanced Data Rates for GSM Evolution (EDGE), High Speed Packet Access (HSPA), etc., and other similar radio communication technologies. Cellular Wide Area radio communication technologies also include “small cells” of such technologies, such as microcells, femtocells, and picocells. Cellular Wide Area radio communication technologies may be generally referred to herein as “cellular” communication technologies. It is understood that exemplary scenarios detailed herein are demonstrative in nature, and accordingly may be similarly applied to various other mobile communication technologies, both existing and not yet formulated, particularly in cases where such mobile communication technologies share similar features as disclosed regarding the following examples. The term “network” as utilized herein, e.g. in reference to a communication network such as a mobile communication network, encompasses both an access section of a network (e.g. a radio access network (RAN) section) and a core section of a network (e.g. a core network section). The term “radio idle mode” or “radio idle state” used herein in reference to a mobile terminal refers to a radio control state in which the mobile terminal is not allocated at least one dedicated communication channel of a mobile communication network. The term “radio connected mode” or “radio connected state” used in reference to a mobile terminal refers to a radio control state in which the mobile terminal is allocated at least one dedicated uplink communication channel of a mobile communication network. Unless explicitly specified, the term “transmit” encompasses both direct (point-to-point) and indirect transmission (via one or more intermediary points). Similarly, the term “receive” encompasses both direct and indirect reception. The term “communicate” encompasses one or both of transmitting and receiving, i.e. unidirectional or bidirectional communication in one or both of the incoming and outgoing directions. Beamforming systems have been targeted as a potentially important component in high frequency next-generation communication networks such as millimeter wave (mmWave) and other so-called “5G” radio technologies. These radio technologies may operate at carrier frequencies of 30 GHz and above, and may need to rely on high beamforming gains in order to compensate for the high path loss associated with carrier frequencies in these ranges. Beamforming systems may perform processing in one or both of the baseband and RF domains to shape antenna array beam patterns. FIGs. 1 and 2 show two simplified beamforming approaches as deployed for an exemplary four-element antenna array. Although the following description may focus on a transmit beamforming context, skilled persons will appreciate the ability to likewise use an analogous implementation for receive beamforming, which may include combining the signals received at the antenna elements according to a complex weight array in order to adjust the received beam pattern. FIG. 1 illustrates a simplified digital baseband beamforming architecture that digitally applies complex beamforming weights (composed of both a gain and phase factor) in the baseband domain. As shown in FIG. 1, digital beamformer 102 may receive baseband symbol s and subsequently apply a complex weight vector p_BB=[¦(a_1&a_2&a_3&a_4 )]^T to s to generate p_BB s, where each element a_i,i=1,2,3,4 is a complex weight (comprising a gain factor and phase shift). Accordingly, each resulting element [¦(a_1 s&a_2 s&a_3 s&a_4 s)]^T of p_BB s may be baseband symbol s multiplied by some complex weight a_i. Digital beamformer 102 may then map each element of p_BB s to a respective RF chain of RF system 104, which may each perform digital to analog conversion (DAC), radio carrier modulation, and amplification on the received weighted symbols before providing the resulting RF symbols to a respective element of antenna array 106. Antenna array 106 may then wirelessly transmit each RF symbol. This exemplary model may also be extended to a multi-layer case where a baseband symbol vector s containing multiple baseband symbols s_1, s_2, etc., in which case baseband precoding vector p_BB may be expanded to a baseband precoding matrix pBB for application to baseband symbol vector s. In this case, a_i,i=1,2,3,4 are row vectors, and p_BB s=[¦(a_1 s&a_2 s&a_3 s&a_4 s)]^T. Thus, after multiplying p_BB and s, the overall dimension is the same as the overall dimension at the output of digital beamformer 102. The below descriptions thus refer to digital beamformer 102 as p_BB and transmit symbol/vector as s for this reason while this model can be extended to further dimensions as explained. By manipulating the beamforming weights of p_BB, digital beamformer 102 may be able to utilize each of the four antenna elements of antenna array 106 to produce a steered beam that has a greater beamgain compared to a single antenna element. The radio signals emitted by each element of antenna array 106 may combine to realize a combined waveform that exhibits a pattern of constructive and destructive interference that varies over distances and direction from antenna array 106. Depending on a number of factors (including e.g. antenna array spacing and alignment, radiation patterns, carrier frequency, etc.), the various points of constructive and destructive interference of the combined waveform may create a focused beam lobe that can be “steered” in direction via adjustment of the phase and gain factors a_i of p_BB. FIG. 1 shows several exemplary steered beams emitted by antenna array 106, which digital beamformer 102 may directly control by adjusting p_BB. Although only steerable main lobes are depicted in the simplified illustration of FIG. 1, digital beamformer 102 may be able to comprehensively “form” the overall beam pattern including nulls and sidelobes through similar adjustment of p_BB. In so-called adaptive beamforming approaches, digital beamformer 102 may dynamically change the beamforming weights in order to adjust the direction and strength of the main lobe in addition to nulls and sidelobes. Such adaptive approaches may allow digital beamformer 102 to steer the beam in different directions over time, which may be useful to track the location of a moving target point (e.g. a moving receiver or transmitter). In a mobile communication context, digital beamformer 102 may identify the location of a target User Equipment (UE) 108 (e.g. the direction or angle of UE 108 relative to antenna array 106) and subsequently adjust p_BB in order to generate a beam pattern with a main lobe pointing towards UE 108, thus improving the array gain at UE 108 and consequently improving the receiver performance. Through adaptive beamforming, digital beamformer 102 may be able to dynamically adjust or “steer” the beam pattern as UE 108 moves in order to continuously provide focused transmissions to UE 108 (or conversely focused reception). Digital beamformer 102 may be implemented as a microprocessor, and accordingly may be able to exercise a high degree of control over both gain and phase adjustments of p_BB through digital processing. However, as shown in FIG. 1 for RF system 104 and antenna array 106, digital beamforming configurations may require a dedicated RF chain for each element of antenna array 106 (where each RF chain performs radio processing on a separate weighted symbol a_i s provided by digital beamformer 102); i.e. N_RF=N where N_RF is the number of RF chains and N is the number of antenna elements. Given the complex assortment of circuitry required for each RF chain (DAC, amplification, mixing, etc.), such digital beamforming approaches may be relatively expensive and power-inefficient. These issues may be compounded as the involved number of antennas increases, which may be particularly problematic for the massive antenna arrays targeted for next-generation technologies that will include tens or even hundreds of antenna elements. Hybrid beamforming has thus been offered to resolve the problematic cost and power consumption issues of digital beamforming. Such hybrid beamforming configurations may utilize a limited number of RF chains (i.e. N_RF